问题补充:
单选题Theyhavebeenskating__________.A.for three hoursB.since three hours agoC.three hours agoD.since three hours
答案:
A解析for 一段时间,为现在完成时态的时间标志,故选
时间:2019-12-16 22:11:04
单选题Theyhavebeenskating__________.A.for three hoursB.since three hours agoC.three hours agoD.since three hours
A解析for 一段时间,为现在完成时态的时间标志,故选