7. It is not clear when __________, although there are many different theories.
A. dinosaurs becoming extinct
B. dinosaurs extinction
C. dinosaurs became extinct ✔
D. did dinosaurs become extinct
Note : I choose the C because there Subject + Verb
8. The professor decided to allow the student to take  the examination a second time
Because the low scores.
Note :(Because)because after because is of.. But in there'nt of
9.  If the driver’s own car __________ damaged, the favorite probably would have won the race.
A. had not been ✔
B. not
C. no had been
D. has no be
Note : past condition
10. Having withdrawn from the race, the candidate decided supporting his opponent despite the opponent's representing the other political party.
Note : the candidate decide to support
11. The soldiers were unable to determine where __________.
A. the jeep had been left✔
B. had been leave the jeep
C. had the jeep been left
D. had the jeep left
Note : A.  because there Subject + Verb
12. The manager was angry because somebody _________.
A. had allowed the photographers to enter the building✔
B. had let the photographers to enter the building
C. permitting the photographers enter the building
D. the photographers let into the building
Note : A. past perfect tense
13. The committee members resented __________ of the meeting.
A. the president that he did not tell them
B. the president not to inform them
C. the president’s not informing them✔
D. that the president had failed informing themselves
Note : Need connection and follow the subject + verb
14.  __________ did Arthur realize that there was danger.
A. Upon entering the store
B. When he entered the store
C. After he had entered the store
D. Only after entering the store✔
Note : (d) Appositive