高中英语现在完成时时态笔记重点大全
单选题(经典例题高频考点-名师出品必属精品)
1、The researchers ______ till midnight every day since the outbreak of the disease to find an effective cure.
A．work
B．will work
C．are working
D．have been working
答案：D解析：考查时态语态。句意：自从疫情爆发以来
,研究者每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。2、I ________ my homework for four hours, but I am not sure whether I can hand it in tomorrow.
A．have done
B．have been doing
C．had been doing
D．had done
答案：B解析：考 ...