
为什么用since不用after?
1个回答
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since与after 都可以用来引导表示从过去某一点开始的时间段词组。它们的不同之处在于:
a)since引导的词组所表示的时间一直延续到说话时为止,因而要与现在完成时连用。例如:He has been there twice since 1982.I have done nothing since six o”clock.
b)after引导的词组所表示的时间是纯系过去,并不延续到说话时,因此要和一般过去时连用。例如:He went home after school.
因此,这里应该填since,而不能填after。
另外,since moving to China,这里把since 看成介词了,since+doing 也就可以了。构成了介宾短语。
实际上该句子应该为:
I have been back twice since I moved to China.
省略用法后,才成为:
I have been back twice since moving to China.
a)since引导的词组所表示的时间一直延续到说话时为止,因而要与现在完成时连用。例如:He has been there twice since 1982.I have done nothing since six o”clock.
b)after引导的词组所表示的时间是纯系过去,并不延续到说话时,因此要和一般过去时连用。例如:He went home after school.
因此,这里应该填since,而不能填after。
另外,since moving to China,这里把since 看成介词了,since+doing 也就可以了。构成了介宾短语。
实际上该句子应该为:
I have been back twice since I moved to China.
省略用法后,才成为:
I have been back twice since moving to China.
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