Mach numbers describe the velocity of airplanes ______ over the speed of sound.
A. have moved B. move C. moving D. moved

Only if these conditions are fulfilled ______to the next stage.
A. can the application proceed B. the application can proceed
C. the application proceed D. do the application proceed

______, Edison didn‟t have much schooling and he was taught by his mother.
A. When was a boy B. A boy was when
C. Was a boy D. When a boy

Top fashion models often spend hundreds of pounds______.
A. getting straightened their teeth B. having got their teeth straightened
C. getting their teeth straightened D. straightening their teeth

The tiny bells on the Christmas tree were ______ in the draught.
A. clanging B. tinkling C. gurgling D. ringing

The military government was determined to ______all opposition.
A. put through B. put out C. put down D. put in

Mrs. Brown: Taxi! Taxi! Taxi driver: ______
A. It's my duty to drive you. B. Where to, Madam?
C. Fancy meeting you here. D. Where are you?

Why do you say the project should be changed even more? Personally, I cannot see the
__________of introducing so many alternations.
A. ground B. reason C. point D. clue

_____________, Sir Isaac Newton described the laws of gravitation.
A. A seventeenth-century scientist
B. When was a seventeenth-century scientist
C. Was a seventeenth-century scientist
D. Who was a seventeenth-century scientist

The instructions from air traffic control were not fully explicit, and ................
A. therefore the pilot made it crash
B. as a result, the pilot made an error and crashed
C. so that the pilot made an error and crashed
D. resulting from the pilot crashing the plane