_______ the investigation, the committee published the report on the cause of the accident.
A. Completed
B. Completing
C. Having completed
D. To have completed
You should be careful when ________ the street in big cities.
A. to cross
B. cross
C. crossing
D. crossed
The policemen entered the building, ________upstairs.
A. looked around and hurrying
B. looking around and to hurry
C. to look around and hurried
D. looking about and hurrying
The conference ___________in Beijing last week is bound to be a great success.
A. discussed
B. discuss
C. discussing
D. to discuss