________.

A．at the beginning B．on one's own

C．in the end D．without help

5．The underlined word "colloquial" in Para.2 means "________"．　

A．oral B．informal

C．formal D．written

6．It can be inferred from the passage that ________.

A．idioms are the most important part in a language

B．the writer is not very willing to use idioms

C．nonnative speakers should learn more idioms

D．there are no ways to master idioms

7．How did the writer develop the passage?

A．By inferring. B．By comparing.

C．By listing examples. D．By giving explanations.