31. What does this passage mainly talk about?

A. 　 Parents must take the electronic products away from their children

B. 　 Parents stop the teenagers from using any electronic product

C. 　 Teenagers should decide not to use the electronic products

D. 　 Teenagers should spend less time on the electronic products

A. 　 How

B. 　 How a

C. 　 What

D. 　 What a

A. 　 wait

B. 　 waited

C. 　 to wait

D. 　 waiting

A. 　 In 1820.

B. 　 In 1854.

C. 　 In 1860.

D. 　 In 1974.

A. 　 stone

B. 　 flower

C. 　 umbrella

D. 　 postcard

A. 　 American young adults are likely to follow the suit of their parents

B. 　 most American people never make major decisions for their children

C. 　 American young adults possess cultural values of independence

D. 　 once a young person steps into his twenties， he will leave his home permanently

A. 　 specially

B. 　 especially

C. 　 strangely

D. 　 essentially

A. 　 There are 20-25 students in the same class.

B. 　 They meet twice (两次) every week.

C. 　 We can find some teachers＇ pictures on the wall.

D. 　 Students can talk with English or American people there.

A. 　 dwellers

B. 　 veterans

C. 　 friskers

D. 　 suspects

A. 　 spreads to

B. 　 spread to

C. 　 spreadable

D. 　 spreading to