1 . I couldn’t focus ________ the experiment.

A．for

B．on

C．with

D．by

2 .          a smiling or sad face added to a post, your reader can "see" your facial expression.

A．When

B．With

C．As

D．By

3 . I couldn’t concentrate ________ the experiment.

A．for

B．on

C．with

D．by

4 . Nothing is so easy as __________ parents to raise their expectations of their children too high.

A．as

B．by

C．for

D．to

5 . If you really have to leave during the meeting, you’d better leave ____ the back door.

A．for

B．by

C．across

D．out

6 . Let’s learn to use the problem we are facing      a stepping-stone to future success.

A．to

B．for

C．as

D．by

7 . Valentine’s Day is a day named ______ Valentine who was a priest in the third century Rome.

A．of	B．with
C．after	D．by

8 . As time went _______, she became more and more interested in English.        (　　)

A．by

B．down

C．up

D．off

9 . ________ stopping polluting the earth ________ hope to live in a better environment.

A．Only to; we can	B．Only to; can we
C．Only by; can we	D．Only by; we can

10 . _____ his accent , he is from the south of China.

A．Judged by

B．Judged from

C．To be judged by

D．Judging from