for 和since

since意為“從······時(shí)起”,，后接表示過(guò)去的時(shí)間點(diǎn),，多用于完成時(shí),，而for 表示持續(xù)多長(zhǎng)時(shí)間,，后接時(shí)間段，可用于多種時(shí)態(tài),，但主要用于有延續(xù)性動(dòng)詞的現(xiàn)在完成時(shí)的句子中,。二者有時(shí)可以進(jìn)行轉(zhuǎn)換。請(qǐng)比較：

He has lived in Hefei since ten years ago.

=He has lived in Hefei for ten years. 他在合肥已經(jīng)住了10年了,。

My father has worked in the factory since 1990.我爸爸從1990年起,，一直在這個(gè)工廠(chǎng)工作。