Question

【题目】The researchers ______ till midnight every day since the outbreak of the disease to find an effective cure.

A.workB.will work

C.are workingD.have been working

Answer 1

【答案】D

【解析】

考查时态语态。句意：自从疫情爆发以来,研究者毎天都忙到深夜以找到有效的治愈方法。 时间状语since the outbreak of the disease提示用完成时态, till midnight表示动作的持续性,故用现在完成进行时,故选D。