diff --git a/src/Narsese/Sentences/stamp.jl b/src/Narsese/Sentences/stamp.jl
index 875bdd4..5345566 100644
--- a/src/Narsese/Sentences/stamp.jl
+++ b/src/Narsese/Sentences/stamp.jl
@@ -9,7 +9,8 @@
 # 导出
 export STAMP_TIME_TYPE, TIME_ETERNAL
 export AbstractStamp, Stamp
-export StampBasic
+export StampBasic, StampPythonic
+export get_evidential_base, get_creation_time, get_put_in_time, get_occurrence_time
 
 
 """
@@ -60,6 +61,26 @@ const STAMP_TIME_TYPE::DataType = UInt # 根据PyNARS的语法要求，改为「
 """
 TIME_ETERNAL::STAMP_TIME_TYPE = typemin(STAMP_TIME_TYPE)
 
+# 方法集 #
+
+"各个抽象Getter"
+get_evidential_base(s::Stamp) = error("$(typeof(s)): 未实现的`get_evidential_base`方法！")
+get_creation_time(s::Stamp)   = error("$(typeof(s)): 未实现的`get_creation_time`方法！")
+get_put_in_time(s::Stamp)     = error("$(typeof(s)): 未实现的`get_put_in_time`方法！")
+get_occurrence_time(s::Stamp) = error("$(typeof(s)): 未实现的`get_occurrence_time`方法！")
+
+"重定向运算符"
+@inline Base.:(==)(s1::Stamp, s2::Stamp) = Base.isequal(s1, s2)
+"判等の法：各个属性相等"
+@inline Base.isequal(s1::Stamp, s2::Stamp) = (
+    get_tense(s1)           == get_tense(s2) && # 时态相等
+    get_evidential_base(s1) == get_evidential_base(s2) &&
+    get_creation_time(s1)   == get_creation_time(s2) &&
+    get_put_in_time(s1)     == get_put_in_time(s2) &&
+    get_occurrence_time(s1) == get_occurrence_time(s2)
+)
+
+# 具体实现
 
 """
 源：OpenNARS
@@ -121,6 +142,11 @@ struct StampBasic{tense <: AbstractTense} <: AbstractStamp
     end
 end
 
+get_evidential_base(s::StampBasic) = s.evidential_base
+get_creation_time(s::StampBasic)   = s.creation_time
+get_put_in_time(s::StampBasic)     = s.put_in_time
+get_occurrence_time(s::StampBasic) = s.occurrence_time
+
 "类型参数の默认值：无时态⇒「永恒」时态"
 StampBasic(args...) = StampBasic{Eternal}(args...)
 
@@ -211,6 +237,12 @@ struct StampPythonic <: AbstractStamp
     end
 end
 
+get_evidential_base(s::StampPythonic) = s.evidential_base
+get_creation_time(s::StampPythonic)   = s.creation_time
+get_put_in_time(s::StampPythonic)     = s.put_in_time
+get_occurrence_time(s::StampPythonic) = s.occurrence_time
+
+
 begin "方法集"
 
     # 【20230815 16:33:51】函数「get_tense」已在「methods.jl」中定义
@@ -221,7 +253,9 @@ begin "方法集"
     """
     获取时态
     """
-    @inline get_tense(s::StampBasic{S}) where {S} = S
+    @inline (get_tense(::StampBasic{T})::TTense) where {T} = T
+    "Python化的「绝对时态」总是「永恒」"
+    @inline get_tense(s::StampPythonic)::TTense = TenseEternal
     "Python化的「相对时态」：与「发生时间」对比"
     @inline get_tense(s::StampPythonic, reference_time::STAMP_TIME_TYPE)::TTense = (
         reference_time == s.occurrence_time ? 
@@ -231,6 +265,8 @@ begin "方法集"
                     TenseFuture
             )
     )
+    "类型自动转换"
+    @inline get_tense(s::StampPythonic, reference_time::Integer)::TTense = get_tense(s, STAMP_TIME_TYPE(reference_time))
 
     """
     （用于「基础时间戳」）是否是由「固定时刻」
@@ -243,26 +279,5 @@ begin "方法集"
     )
     "【20230815 23:45:19】Python版的暂且恒为true，因为并无「固定的时态」一说"
     @inline is_fixed_occurrence_time(s::StampPythonic) = true
-
-    """
-    判等の法：相等@各个属性
-    """
-    @inline Base.:(==)(s1::StampBasic, s2::StampBasic)::Bool = (
-        typeof(s1)          == typeof(s2) && # 时态相等
-        s1.evidential_base  == s2.evidential_base &&
-        s1.creation_time    == s2.creation_time &&
-        s1.put_in_time      == s2.put_in_time &&
-        s1.occurrence_time  == s2.occurrence_time
-    )
-
-    """
-    判等の法：相等@各个属性
-    """
-    @inline Base.:(==)(s1::StampPythonic, s2::StampPythonic)::Bool = (
-        s1.evidential_base  == s2.evidential_base &&
-        s1.creation_time    == s2.creation_time &&
-        s1.put_in_time      == s2.put_in_time &&
-        s1.occurrence_time  == s2.occurrence_time
-    )
     
-end
\ No newline at end of file
+end
diff --git a/src/Narsese/Sentences/truth.jl b/src/Narsese/Sentences/truth.jl
index dc98c93..d5f146a 100644
--- a/src/Narsese/Sentences/truth.jl
+++ b/src/Narsese/Sentences/truth.jl
@@ -30,9 +30,9 @@ const Truth = ATruth = AbstractTruth
 # 抽象类方法 #
 
 "获取频率f"
-get_f(t::Truth) = error("$t: 未实现的`get_f`方法！")
+get_f(t::Truth) = error("$(typeof(t)): 未实现的`get_f`方法！")
 "获取信度c"
-get_c(t::Truth) = error("$t: 未实现的`get_c`方法！")
+get_c(t::Truth) = error("$(typeof(t)): 未实现的`get_c`方法！")
 
 """
 判等の法：相等@f,c
diff --git a/src/Narsese/Tasks/budget.jl b/src/Narsese/Tasks/budget.jl
index cb08b05..e5c0f87 100644
--- a/src/Narsese/Tasks/budget.jl
+++ b/src/Narsese/Tasks/budget.jl
@@ -33,11 +33,11 @@ const Budget = ABudget = AbstractBudget
 # 抽象类方法 #
 
 "获取优先级p"
-get_p(b::Budget) = error("$b: 未实现的`get_p`方法！")
+get_p(b::Budget) = error("$(typeof(b)): 未实现的`get_p`方法！")
 "获取耐久度d"
-get_d(b::Budget) = error("$b: 未实现的`get_d`方法！")
+get_d(b::Budget) = error("$(typeof(b)): 未实现的`get_d`方法！")
 "获取质量q"
-get_q(b::Budget) = error("$b: 未实现的`get_q`方法！")
+get_q(b::Budget) = error("$(typeof(b)): 未实现的`get_q`方法！")
 
 """
 判等の法：相等@p,d,q
diff --git a/src/Narsese/Terms/methods.jl b/src/Narsese/Terms/methods.jl
index fd0c823..b6c3b02 100644
--- a/src/Narsese/Terms/methods.jl
+++ b/src/Narsese/Terms/methods.jl
@@ -60,7 +60,7 @@ begin "NAL信息支持"
     - 等价于：虚方法/抽象方法
     - 需要被子类实现
     """
-    @inline get_syntactic_complexity(::Term) = error("未定义的计算！")
+    @inline get_syntactic_complexity(t::Term) = error("$(typeof(t))未定义的计算！")
 
     """
     （默认）原子の复杂度 = 1
diff --git a/src/Narsese/use_strict.jl b/src/Narsese/use_strict.jl
index 7f3f2d3..248fefe 100644
--- a/src/Narsese/use_strict.jl
+++ b/src/Narsese/use_strict.jl
@@ -52,7 +52,9 @@ end
 # 临时定义陈述合法性：改变「内联合法性检查」逻辑
 "继承&相似⇒是否为「一等公民」"
 @inline function check_valid(t::Statement{<:TermBasedSTs})
-    ϕ1(t) ≠ ϕ2(t) && ϕ1(t) isa FOTerm && ϕ2(t) isa FOTerm
+    ϕ1(t) ≠ ϕ2(t) &&
+    ϕ1(t) isa FOTerm &&
+    ϕ2(t) isa FOTerm
 end
 
 "继承&相似⇒是否为「一等公民」"
@@ -65,7 +67,9 @@ end
 
 "蕴含&等价⇒是否为「陈述词项」"
 @inline function check_valid(t::Statement{<:StatementBasedSTs})
-    ϕ1(t) ≠ ϕ2(t) && ϕ1(t) isa AbstractStatement && ϕ2(t) isa AbstractStatement
+    ϕ1(t) ≠ ϕ2(t) && 
+    ϕ1(t) isa StatementLike && 
+    ϕ2(t) isa StatementLike
 end
 
 "蕴含&等价⇒是否为「陈述词项」"
@@ -79,7 +83,8 @@ end
 
 "陈述逻辑集、陈述时序集：词项数>1 && 不支持「非陈述词项」"
 @inline function check_valid(t::ACompound{<:StatementBasedCTs})
-    length(t) > 1 && all(term isa StatementLike for term in t)
+    length(t) > 1 && 
+    all(term isa StatementLike for term in t)
 end
 "陈述逻辑集、陈述时序集：词项数>1 && 不支持「非陈述词项」"
 @inline function check_valid_explainable(t::ACompound{<:StatementBasedCTs})
diff --git a/src/Util/Util.jl b/src/Util/Util.jl
index eb11f7c..d031965 100644
--- a/src/Util/Util.jl
+++ b/src/Util/Util.jl
@@ -4,7 +4,7 @@
 module Util
 
 export UNothing
-export @reverse_dict_content, @redirect_SRS, @expectedError
+export @reverse_dict_content, @redirect_SRS, @hasError, @expectedError
 export match_first, match_first_view
 export allproperties, allproperties_generator, allproperties_named, allproperties_named_generator
 export empty_content
@@ -35,6 +35,21 @@ macro redirect_SRS(para::Expr, code::Expr)
     return redirect_SRS(para, code)
 end
 
+"【用于调试】判断「是否出错」（仿官方库show语法）"
+macro hasError(exs...)
+    Expr(:block, [ # 生成一个block，并使用列表推导式自动填充args
+        quote
+            try
+                $(esc(ex))
+                false
+            catch e
+                true
+            end
+        end
+        for ex in exs
+    ]...) # 别忘展开
+end
+
 "【用于调试】判断「期望出错」（仿官方库show语法）"
 macro expectedError(exs...)
     Expr(:block, [ # 生成一个block，并使用列表推导式自动填充args
diff --git a/test/test_construction.jl b/test/test_construction.jl
index e34689a..199685d 100644
--- a/test/test_construction.jl
+++ b/test/test_construction.jl
@@ -7,13 +7,20 @@
 
     @show w i d q o
 
+    p = PlaceHolder()
     @test w == Word(:词项)::Word
     @test i == IVar(:独立变量)::Variable{VTIndependent}
     @test d == DVar(:非独变量)::Variable{VTDependent}
     @test q == QVar(:查询变量)::Variable{VTQuery}
+    @test p == PlaceHolder()::PlaceHolder
     @test o == Operator(:操作)::Operator
     @test n == Interval(+137)::Interval
 
+    # 像占位符
+    @test p == placeholder
+    @test nameof(p) == Symbol()
+    @test nameof_string(p) == ""
+
     # 词项集
     exSet = ⩀(w, d, o)
     inSet = ⊍(n, q, i)
diff --git a/test/test_methods_arrays.jl b/test/test_methods_arrays.jl
index ce81927..1f21a00 100644
--- a/test/test_methods_arrays.jl
+++ b/test/test_methods_arrays.jl
@@ -11,7 +11,7 @@
     @test length(A) == 1
 
     # 测试原子的索引函数
-    @test getindex(A) == A[] == :A
+    @test getindex(A) == A[] == A[typemax(Int)] == A[typemin(Int)] == :A
 
     # 测试除差、像以外的所有复合词项
     for compoundType::Type in [TermProduct, ExtSet, IntSet, ExtIntersection, IntIntersection]
diff --git a/test/test_methods_nal.jl b/test/test_methods_nal.jl
index 757ee75..7bbf16f 100644
--- a/test/test_methods_nal.jl
+++ b/test/test_methods_nal.jl
@@ -15,12 +15,19 @@
         (A→B) in terms_ && (B→C) in terms_ &&
         ((A→B)⇒(B→C)) in terms_
 
+    # 获取所有索引
+    t = ExtSet(A,B,C)
+    @test eachindex(t) == Base.OneTo(3)
+    @test nextind(t, 1) == 2
+    @test prevind(t, 2) == 1
+
     # 是否可交换 #
     @test !is_commutative(StatementTypeInheritance)
     @test !is_commutative(StatementTypeImplication)
     @test is_commutative(StatementTypeSimilarity)
     @test is_commutative(StatementTypeEquivalence)
-
+    
+    @test !is_commutative(Term) # 默认不可交换
     @test !is_commutative(TermProduct)
     @test !is_commutative(ExtImage)
     @test !is_commutative(IntDiff)
@@ -42,6 +49,7 @@
 
     # 是否可重复：默认是`!(是否可交换)`，但**不用于判断陈述** #
 
+    @test is_repeatable(Term) # 默认可重复
     @test is_repeatable(TermProduct)
     @test is_repeatable(ExtImage)
     @test is_repeatable(SeqConjunction)
@@ -127,4 +135,35 @@
 
     @test EquivalenceRetrospective(A→B, B→A) == EquivalencePredictive(B→A, A→B)
 
+    # 语句&任务 #
+
+    # 时间戳 #
+
+    sb = StampBasic()
+    sp1 = StampPythonic()
+
+    @test sb == sp1 # 默认值应该相等
+    @test sb !== sp1 # 不全等
+
+    sp2 = StampPythonic(occurrence_time = 1)
+    # 相对时序
+    @test get_tense(sp2) == Eternal # 默认永恒
+    @test get_tense(sp2, 0) == Future  # sp2 是 0 的未来
+    @test get_tense(sp2, 1) == Present # sp2 是 1 的现在
+    @test get_tense(sp2, 2) == Past    # sp2 是 2 的过去
+
+    @test sp2 == deepcopy(sp2)
+    @test sp1 != sp2
+
+    # 方法重定向
+    for t in test_set.tasks, method_name in [:get_term, :get_stamp, :get_tense, :get_punctuation, :get_truth, :get_syntactic_complexity]
+        @test @eval $method_name($t) == $method_name(get_sentence($t))
+    end
+    for t in test_set.tasks, method_name in [:get_p, :get_d, :get_q]
+        @test @eval $method_name($t) == $method_name(get_budget($t))
+    end
+    for t in test_set.sentences, method_name in [:get_syntactic_complexity]
+        @test @eval $method_name($t) == $method_name(get_term($t))
+    end
+
 end
diff --git a/test/test_methods_validity.jl b/test/test_methods_validity.jl
index 1ced43c..27f37ae 100644
--- a/test/test_methods_validity.jl
+++ b/test/test_methods_validity.jl
@@ -54,4 +54,14 @@
     @test @expectedError ParConjunction(A→B, C→D, A↔D, D→o, B→C, w)
     @test @expectedError SeqConjunction(A→B, D→o, B→C, A↔D, C→D, w)
 
+    # 所有词项的「可解释🆚非解释」「内部🆚外部」严格性应该相互等价
+    for term::Term in test_set.terms
+        @test (
+            check_valid(term) == 
+            !(@hasError check_valid_explainable(term)) == 
+            check_valid_external(term) == 
+            !(@hasError check_valid_external_explainable(term))
+        )
+    end
+
 end
diff --git a/test/test_narsese.jl b/test/test_narsese.jl
index 099842e..4ecc2f3 100644
--- a/test/test_narsese.jl
+++ b/test/test_narsese.jl
@@ -19,6 +19,9 @@
 
     # 类型 #
     include("test_types.jl")
+    
+    # API #
+    include("test_narsese_api.jl")
 
     # 词项与数组等可迭代对象的联动方法 #
     include("test_methods.jl")
diff --git a/test/test_narsese_api.jl b/test/test_narsese_api.jl
new file mode 100644
index 0000000..9af5dda
--- /dev/null
+++ b/test/test_narsese_api.jl
@@ -0,0 +1,35 @@
+(@isdefined JuNarsese) || include("commons.jl") # 已在此中导入JuNarsese、Test
+
+# 词项接口：用于后续扩展自定义词项/语句/任务 #
+@testset "Narsese/API" begin
+
+    # 定义几个没实现方法的抽象类型，以便测试在「调用未实现方法的报错」 #
+    struct TestTerm <: Term end
+    struct TestTruth <: Truth end
+    struct TestBudget <: Budget end
+    struct TestStamp <: Stamp end
+
+    t = TestTerm()
+    tt = TestTruth()
+    ts = TestStamp()
+    tb = TestBudget()
+
+    @test @expectedError get_syntactic_complexity(t)
+    
+    @test @expectedError get_f(tt)
+    @test @expectedError get_c(tt)
+
+    @test @expectedError get_p(tb)
+    @test @expectedError get_d(tb)
+    @test @expectedError get_q(tb)
+
+    @test @expectedError get_evidential_base(ts)
+    @test @expectedError get_creation_time(ts)
+    @test @expectedError get_put_in_time(ts)
+    @test @expectedError get_occurrence_time(ts)
+
+    # 测试一些「抽象词项的默认值」 #
+    @test !is_commutative(t) # 默认不可交换
+    @test is_repeatable(t) # 默认可重复
+
+end