We ______ happily when we heard a loud noise outside the door last night.
A.chat B.chatted C.are chatting D.were chatting
There are many tree heroes in China. They ______ millions of trees for almost 20 years.
A.plant B.planted C.have planted D.are planting
If we learn more about DNA, we ______ more diseases.
A.treat B.treats C.will treat D.were treating
James enjoys reading, and he ______ novels on his way to work on the subway every day.
A.read B.reads C.is reading D.will read
Wang Xuan is a famous computer scientist. He his research of laser typesetting in 1975.
A.start B.started C.is starting D.will start
—______do you usually have dinner?
—At about 6 p.m.
A.When B.Where C.Why D.How
