A.change their user’ temperament
B.cause some mental malfunction
C.change their users’ social behavior
D.damage their users’ emotions

A.they are indispensable in everyday communications.
B.they make them look more stylish.
C.they keep the users alert all the time.
D.they cannot be replaced by regular phones.

A.I couldn’t understand his book because I didn’t read it.
B.I wouldn’t have understood what he was saying if I hadn’t read his book.
C.I was had to understand his book so I didn’t understand what he was saying.
D.If I had read his book, I would have understood what he was saying.

A.As long as the class finished, the students ran out, screamed and shouted.
B.No sooner did the class finish than the student ran out, screamed and shouted.
C.As soon as the class had finished, the student ran out, screamed and shouted.
D.If the class was over, the students would run out, scream and shout.

A.He is being asked to make questions by the police at the headquarters.
B.The police are making questions about him at headquarters.
C.The police are trying to get information from him at the headquarters.
D.Many questions are raised about him by the police at the headquarters.

A.submit
B.omit
C.admit
D.permit

A.surprise
B.surprisingly
C.surprising
D.surprised

A.the cells and tissues of the brain.
B.the resident memory.
C.the mobility of the mind and the body.
D.the arteries of the brain.

A.produce
B.bring out
C.form
D.terminate

A.wear a backpack
B.praise yourself
C.criticize yourself
D.check up your back