The graduating students are busy _______ material for their reports.

　A. collect　               B. to collect　               C. collected　                     D. collecting

The ground is _______ with _______ leaves.　

　A. covering, falling     B. covered, falling　       C. covered, fallen            D. covering, fallen

 _______ a post office, I stopped _______ some stamps.　

　A. Passed, buying　 B. Passing, to buy　       C. Having passed, buy    D. Pass, to buy

The children were last seen ___ by the river.                                                                      

A. to play    B. played    C. play    D. playing

He can’t help __ housework, for he is busy __ for the examination.

   A. doing; preparing   B.  to do; to prepare   C. doing; to prepare   D. to do; preparing

Tom kept quiet about the accident  _______      lose his job.

A. so as not to              B. so not as to       C. so as to not              D. not so as to

I happened_______with him when he was hit by a stone.

　　A.I was talking             B.talking              C.to talk               D.to be talking

— Shall I close the window for you?

   — No. I am used to ______ with the window ______.

  A. sleeping; open      B. sleep; opening                C. sleeping; opened           D. sleep; open

Were you _______ when you saw that wild animal?

　A. fright　　　               B. frightening　　　        C. frightened　　　        D. frighten

The student corrected his paper carefully, _______ the professor's suggestions.   

　A. follow　               B. following 　          C. followed　                     D. being followed