一个人熟知某种物品的惯常用途后，很难想到该物品的其它用途，这种现象称为（）。

阅读下列短文，从每题所给的四个选项（A、B、C和D）中选出最佳选项。

Great scientists before us didn’t get everything from school. Their teachers only showed them the way. Edison didn’t even finish primary school. But they were all so successful. They invented so many things for mankind. The reason for their success is that they knew how to study. They read books that were not taught at school. They would ask many questions as they read. They did thousands of experiments. They worked hard all their lives, wasting not a single moment. Above all, they knew how to use their brain.

小题1:People go to school to _________.

A．learn several subjects

B．make a living

C．get an education

D．learn from teachers小题2:According to the passage, the most important thing a teacher should do is _________.

A．to teacher his students everything he knows

B．to teach the students how to think

C．to know everything they want to know

D．to teach the students how to work out a math problem小题3:To work out a math problem, you need to know _________.

A．only a certain formula

B．a certain fact

C．some facts

D．the way to solve it小题4:Why were many scientists so successful?

A．They received good education.

B．They were very clever.

C．They knew how to learn.

D．They learned lots of facts and formulas.小题5:How did great scientists study?

A．They read a lot of books and asked many questions while reading.

B．They did thousands of experiments.

C．They always worked hard and never wasted time.

D．All of the above.

人类文明的发祥地之一的“两河流域”是指（　　）

A．印度河和恒河

B．恒河和幼发拉底河

C．黄河和长江

D．幼发拉底河和底格里斯河

中性氨基酸的等电点范围是（）

A、7.6~10.6；

B、6.3~7.2；

C、2.8~3.2；

D、5.5~6.3

精馏的必要条件有（），（），（）三项。

服务贸易外汇收支涉及的交易单证应符合国家法律法规和通行商业惯例的要求，主要包括（）。

A.包含交易标的、主体等要素的合同（协议）

B.发票（支付通知）或列明交易标的、圭体、金额等要素的结算清单（支付清单）

C.工商营业执照

D.组织机构代码证

E.缴税凭证