1. In America, if _______ friend has invited you to drop in at any time, it is _______ best to call
before visiting to make sure it is convenient for him.
A. a; a B. the; a C. a; 不填 D. the; 不填
2. Some people would rather ride bikes as bike riding has _______ of the troubles of taking buses.
A. nothing B. none C. some D. neither
3. Parents are advised to take pressure _______ a child and give him or her some encouragement before an exam.
A. off B. over C. from D. to
4. －You can’t imagine _______ fantastic fun web chatting is.
－Really? But it may cause a lot of trouble sometimes.
A. what B. how C. why D. whether
