A．Did; see B．Do; seeC．Have; saw D．Have; seenHi, Bob! I ……

单项选择题It is essential that these application forms back as early as possible.

单项选择题Duty is an act or a course of action that people （） you to take by social customs, law or religion.

A. persuade
B. request
C. instruct
D. expect

单项选择题—I thought you wouldn't mind. — Well, as a matter of fact, I don't, but you ______ me first.

单项选择题All of them try to use the power of the workstation ______ information in a more effective way.

单项选择题We（）on this project for four hours. Let's have a rest.

A. are working
B. have been working
C. worked
D. had worked

单项选择题Galileo lived in the City of Pisa, ______ there is a leaning tower about 180 feet ______.

单项选择题She didn't see me come and went on ______ her newspaper.

单项选择题The air of countryside is cleaner than ______ of city, but I don't like to live ______ far.

单项选择题Madame Curie's ______ encouraged many women to study science, and many of them ______.

单项选择题Who is it up ______ decide ______ whether to go or not