16. This is what you should bear in mind: Don’t _____ a salary increase before you actually get it.
A) hang on    B) draw on       C) wait on         D) count on

17. The ship’s generator broke down, and the pumps had to be operated _____ instead of mechanically.
A) artificially  B) automatically  C) manually        D) synthetically

18. The little girl was so frightened that she just wouldn’t ______ her grip on my arm.
A) loosen     B) remove       C) relieve          D) dismiss

19. He never arrives on time and my ______ is that he feels the meetings are useless.
A) preference B) conference    C) inference        D) reference

20. Mrs. Smith was so ______ about everything that no servants could please her.
A) specific    B) special       　 　C) precise         D) particular

16.D) count on    17.C) manually    18.A) loosen    19.C) inference    20.D) particular