Susie_07
春芽
共回答了23个问题采纳率:95.7% 举报
since 和when 用法是不同的.
since 意为:自从,主要用于完成时态中,做完成时的时间状语.其后可跟短语,也可跟从句,若跟从句,要用一般过去式.
如:I have lived here since 1999.(跟短语)
I have lived here since I found a job in this city.(跟过去时的从句)
when意为:当.时候,做时间状语.其后常跟从句.
如:When Spring Festival comes,we all celebrate it in all kinds of ways.
尤其注意,当表达完成时时,上述since 不可替换成when,否则前面主句就要改为过去式.这是因为when 和since有固定的时态搭配,通常when 不和完成时主句搭配.since不和过去时主句搭配.
1年前
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