在現(xiàn)在完成時(shí)的句子中,since后面接過去的某一具體時(shí)間點(diǎn),“since+過去的時(shí)間點(diǎn)”表示從這一時(shí)間點(diǎn)到現(xiàn)在的一段時(shí)間.
這一時(shí)間點(diǎn)如果用時(shí)間狀語從句來表示,這一從句的謂語要用短暫性動(dòng)詞,并且要用一般過去時(shí).
如：
I have seen a lot of friendly people since 1980/since I came to China/ since10 months ago/since I moved to the city in 2006.
for直接接一段時(shí)間.如：
I've been in China for 5 years/for 8 weeks/for a long time.