Question

----This returned Chinese scholar has become one of the top experts in this field.
----Yes,I know him very well.He____in Africa with animals for eight years.

A．has worke

B．had worked

C．worked

D．has been working

Answer 1

C

since，for作為連詞，引導(dǎo)時(shí)間狀語(yǔ)（從句）如果謂語(yǔ)動(dòng)詞是延續(xù)性的一般過(guò)去時(shí)，其表達(dá)的含義是"從這個(gè)動(dòng)作結(jié)束以來(lái)"，恰好和動(dòng)詞的詞義相反，具有否定的含義；如果謂語(yǔ)動(dòng)詞是非延續(xù)性的一般過(guò)去時(shí)，其表達(dá)的含義是"從這個(gè)動(dòng)作開(kāi)始以來(lái)"，恰好和動(dòng)詞的詞義一致，具有肯定的含義
It is 3 years since her husband worked as a news journalist. 她丈夫不當(dāng)記者已三年了。
It is 5 years since I joined the army. 我在部隊(duì)已服役五年了。（仍在軍隊(duì)服役）