John can’t attend the party _______ at Tom’s house now because he’s preparing the speech for the party _______ at Jim’s house tomorrow．

A．being held; to be held

B．to be held; to be held

C．to be held; held

D．held; being held

I often think of the hours _______ I stayed with you, _______ have had a great effect on my life．

A．that; which

B．which; who

C．which; that

D．when; which

By the time he leaves university, he will have gained much working experience _______ he takes a part-time job．

A．so long as

B．unless

C．even though

D．in case

_______ on a mobile phone can you ring whomever you want to talk with anywhere．

A．Only

B．When

C．Still

D．Yet

For the labor-importing countries, the flow of labor may _______ stronger job competition．

A．stick to

B．come from

C．lead to

D．begin with

The seller would sell the skirt for fifty dollars, but the customer _______ only half that price．

A．asked

B．charged

C．sold

D．offered

_______ number of books I have written these years is twenty, and _______ number of them are about English grammar．

A．A; a

B．A; the

C．The; the

D．The; a

George was responsible for the accident because he didn't give a ________ to other drivers．

A．notice

B．signal

C．symbol

D．mark

His father sent him to Paris to study law, but ________ he developed his love for the theatre．

A．besides

B．instead

C．moreover

D．therefore

Eating too much fat can ________ to heart disease and high blood pressure．

A．devote

B．attend

C．contribute

D．turn