d I was twenty 從宏觀上來看就是一個(gè)時(shí)間點(diǎn),而連詞since的后面就要求加時(shí)間點(diǎn),故正確.您好！since+一段時(shí)間+ago也是可以用于完成時(shí)的。since不可以+一段時(shí)間但since的后面接ago 是可以用時(shí)間點(diǎn)的如 They have lived in that house since two years ago.給個(gè)例句如何？如 They have lived in that house since two years ago.沒錯(cuò)。這個(gè) two years ago是指發(fā)生動(dòng)作lived的第一天，從宏觀上來說，它是實(shí)質(zhì)仍然是一個(gè)時(shí)間點(diǎn)了。明白了。非常感謝您！我在學(xué)新二。語法強(qiáng)化上的題。請(qǐng)問如何與您聯(lián)系請(qǐng)教？