—_____ do you go to the school library? —Once a week.
The Xiamen-Shenzhen high speed railroad will run________eight cities. A.across B.through C.over
When the door bell ________I was listening to music.
Yesterday I met Sandy.We________each other since________middle school.
—What did Bob ask you just now? —He wanted to know how long________when he reached the cinema. A.the film had started B.the film will start C.the film had been on
Helen________her keys in the office so she had to wait until her husband________home.