Tom, clean up the broken glass _________ someone walks on it.
Tom ________ in the library every night over the last three months.(2011·北京)
In order to find the missing child,villagers ________ all they can over the past five hours.(2012·安徽)
—Hi, Susan, where were you at lunch time?I ________ a seat for you in the coffee shop.—Oh, sorry to miss you.My political science class ran longer than usual.
—Mum, you should have taken me to the park this morning.—I had planned to, but I couldn't afford the time.I ________ a lecture.
—When did the computer crash?—This morning,while I ________ the reading materials downloaded from some websites.(2012·福建)