The hill ____ is covered with tress is called Huang Hill.
| A．of which top | B．whose the top |
| C．whose top | D．top which |
Tom ________ in the library every night over the last three months.(2011·北京)
| A．works | B．worked |
| C．has been working | D．had been working |
In order to find the missing child，villagers ________ all they can over the past five hours.(2012·安徽)
| A．did | B．do |
| C．had done | D．have been doing |
—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.
| A．am saving | B．was saving |
| C．had saved | D．have saved |
—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.
| A．had given | B．gave |
| C．was giving | D．would give |
—When did the computer crash?
—This morning，while I ________ the reading materials downloaded from some websites.(2012·福建)
| A．have sorted | B．was sorting |
| C．am sorting | D．had sorted |