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
