I earn only 50 dollars a week, ________ she earns 80 dollars．

A．when

B．while

C．as

D．since

There is ________ argument on the spreading easy access to ________ Internet．

A．不填，the

B．an;the

C．the;an

D．the;不填

Today we have too many choices of communication through advanced technology, but we seem ________ the joy of communicating face to face．

A．losing

B．to be losing

C．to be lost

D．having lost

John found it a challenge to meet the needs of the boss．________ , he had no way to satisfy him．

A．In need

B．In case

C．In no time

D．In other words

The scene of the film ________ memories of the period when I was working on a farm．

A．called up

B．called on

C．called for

D．called in

I'm quite ________ to office work．Can you offer me some suggestions?

A．familiar

B．fresh

C．similar

D．sensitive

Hearing the news, I realized ________ terrible problems we would face．

A．how

B．which

C．what

D．that

________ it was hard for children to leave family and friends, many families chose to send their children to America．

A．Because

B．Although

C．If

D．As

The couple are used to getting up before dawn, ________ it is still dark outside．

A．as

B．but

C．which

D．when

AIDS control and prevention is a ________ to China as well as the whole world．

A．surprise

B．challenge

C．reaction

D．threat