13.We can＇t _________this math problem. Can you help us?

A. 15

B. 18

C. 20

D. 22

A. 　 破产

B. 　 损坏

C. 　 违反

D. 　 折断

A. 　 understanding

B. 　 feedback

C. 　 complain

D. 　 resistance

A. 　 Person-to-person auction sites are less popular than business-to-business sites.

B. 　 Business-to-person auction sites are less popular than person-to-person sites.

C. 　 For person-to-person auction sites， the websites is the owner of goods.

D. 　 For business-to-person auction sites， the website is the owner of the goods.

A. 　 obligation

B. 　 potential

C. 　 ability

D. 　 talent

A. 　 in; for

B. 　 in; as

C. 　 on; as

D. 　 to; for

A. 　 challenge is nothing before any life of my creation

B. 　 there is no challenge that can’t be overcome for my created life

C. 　 I will give any of my creations a hand to handle their challenge

D. 　 you will not meet a challenge without my handling it

A. 　 listen to

B. 　 listened to

C. 　 was listening to

D. 　 am listening to

A. 　 it is not easy to have a friendly relationship with people when there is a marked difference in age and background

B. 　 he degreed of friendship between people and the reason for their shared interests can vary greatly

C. 　 friends need to know all these things

D. 　 these are the most important factors to make friends

A. 　 Government investment does not meet school＇s needs.

B. 　 Skilled students are moving for private schools.

C. 　 Qualified teachers are far from adequately paid.

D. 　 Training of students＇ basic skills is neglected.