关于轮换式的因式分解题第一题:a^2(b+c)+b^2(c+a)+c^2(a+b)—(a^3+b^3

Which of the following statements is NOT mentioned as a reason of the disappearance of languages？

A．Government policies discourage native tongues to develop.

B．Diseases and natural disasters destroy native tongues.

C．Immigrants tend to desert their native tongues.

D．Pressure from economic development stimulates the disappearance of languages.

请帮忙给出正确答案和分析，谢谢！

自然通风气流下降式烤房通风排湿即打开()。

A.进风洞

B.排湿管

C.天窗

D.风机

此题为多项选择题。请帮忙给出正确答案和分析，谢谢！

Its very likely that you will make mistakes in foreign countries______.

A．by following the conventions in your society

B．by imitating all their behaviors

C．with too much knowledge on conventions

D．without knowing their behaviors

请帮忙给出正确答案和分析，谢谢！

What is the mans request？

A．To have breakfast in the room.

B．To pay the bill when checking out.

C．To sign the name in the morning.

D．To use a new credit card for the room.

请帮忙给出正确答案和分析，谢谢！

What does the man say about watching classic movies？

A．It is helpful in practicing one"s pronunciation.

B．It can make people relaxed.

C．It can enrich their college life.

D．It is the source of classic music.

请帮忙给出正确答案和分析，谢谢！