大师作文网It is 3 years since he joined the army.为什么用is不用has been
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It is 3 years since he joined the army.为什么用is不用has been
since是现在完成时的标志,但是since+过去的时间点或是过去时态从句,下面的例句是摘抄的,你参考下.我觉的,两个应该都行,你说的应该也是对的.因为joined 也是瞬时动词.
It is / has been + 一段时间 +since 从句.例如：
It is / has been three years since we saw each other last time.
我们上一次见面是在 3 年前.
It is four years since I became a student.
我上了 4 年学了.
（注意：状语从句中常用短暂性动词的一般过去时作谓语动词）
注意：since 从句里的谓语动词是瞬间动词时,表示这段时间从该动作开始时算起； since 从句里的谓语动词是延续性 / 表状态的动词时,则表示这段时间从动作结束时算起.例如：
It's five years since he lived here.
他离开这儿有 5 年了.（ live 为延续性动词）
It's ten years since he joined the army.
他参军已有 10 年了.（ join 为瞬间动词）
It is / has been + 一段时间 +since 从句.例如：
It is / has been three years since we saw each other last time.
我们上一次见面是在 3 年前.
It is four years since I became a student.
我上了 4 年学了.
（注意：状语从句中常用短暂性动词的一般过去时作谓语动词）
注意：since 从句里的谓语动词是瞬间动词时,表示这段时间从该动作开始时算起； since 从句里的谓语动词是延续性 / 表状态的动词时,则表示这段时间从动作结束时算起.例如：
It's five years since he lived here.
他离开这儿有 5 年了.（ live 为延续性动词）
It's ten years since he joined the army.
他参军已有 10 年了.（ join 为瞬间动词）
It is 3 years since he joined the army.为什么用is不用has been
看到一句It is 3 years since he joined the army.和一句It has been th
It is three years since he joined the army.为什么是用joined而不是用ha
it is four years since I joined the army.这里的is,为什么不用was呢?
It __four years since i joined the army.这里的is,为什么不用was呢?
用since的话,本句应该是：It is ten years since he joined the army.
it has been 5 years since he joined the army 是表肯定还是否定呢 求教英语大
It is said _______ he has joined the army.
15、 It _____ ten years since he left the army .A.is B.has C.
It _____ ten years since he left the army . A. is B. has C.
It is ten years since he ____(join) the army
1.It is two years ＿I joined the army.A.before B.since C.that