1.()There are two possible explanations to ________ the change in speed,but we don't know which one is right.
2.()_________ for his help,we couldn't have overcome the difficulties.
B.Hadn't it been
C.Had it not been
3.()It was ________ for Jim to finish the test paper within an hour because there were too many new words in it.
A.out of question
D.out of the question
4.()It is in Iran ________ the family members participate in the wedding preparations.
5.()________ put down the receiver _______ the telephone rang again.
A.Scarcely had she .……than
B.Scarcely did she .……than
C.She scarce had .……than
D.Scarce had she .……than
6.()He had been interested in history since his childhood,so he specialized _______ history when he was in college.
7.()The meeting ended _________ his lecture on high education.
8.()_________,he was not able to work out the puzzle.
A.However he tried hard
B.Whatever he tried hard
C.However hard he tried
D.How hard he tried
9.()_________ such enormous danger,he still remained as calm as usual.
A.In the face of
B.In face of
C.In the face with
D.In face with
10.()This is one of the most wonderful songs______ I have ever heard.