Question

【題目】With the help of high technology, more and more new substances ___in the past few years.

A. discoveredB. have discovered

C. had been discoveredD. have been discovered

Answer 1

【答案】D

【解析】

考查時(shí)態(tài)語(yǔ)態(tài)。句意：因?yàn)橛懈呖萍嫉膸椭�，在最近幾年中，越�?lái)越多的新物質(zhì)已經(jīng)被發(fā)現(xiàn)了。根據(jù)時(shí)間狀語(yǔ)in the past few years,說(shuō)明使用現(xiàn)在完成時(shí)。根據(jù)句意新物質(zhì)和發(fā)明之間用被動(dòng)形式。故D正確。