问题 单项选择题

9~10题基于以下题干。
3位高中生赵、钱、孙和3位初中生张、王、李参加一个课外学习小组。可选修的课程有文学、经济、历史和物理。
赵选修的是文学或经济;王选修物理:如果一门课程没有任何一个高中生选修,那么任何一个初中生也不能选修该课程;如果一门课程没有任何初中生选修,那么任何一个高中生也不能选修该课程;一个学生只能选修一门课程。

如果上述断定为真,且钱选修历史,以下哪项一定为真

A.孙选修物理。

B.赵选修文学。

C.张选修经济。

D.李选修历史。

答案

参考答案:A

解析: 如果有一个初中生选修某门课程,那么就有一个高中生也选修该课程;反之亦然。已知初中生王选修物理,所以有一个高中生也选修物理,即赵、钱或孙选修物理。又因为一个学生只能修一门课程,已知钱选修历史,所以钱不选修物理:赵选修文学或经济,所以赵不选修物理。因此,可推出孙选修物理。

阅读理解

Every electronic gadget (小玩意) needs good memory. A music player stores songs, albums and playlists. A computer holds schoolwork and programs and remembers how far a player has advanced in his or her favorite game. Mobile phones store names, numbers and hundreds of texts.

Now, scientists in California say they have come up with a way to turn a living cell into a memory device.

It can store only one tiny bit of information, but it’s a start. In the future, a cell-based gadget might travel through the body and record measurements. The benefit to human health could be big: the right tool, for example, might record the earliest signs of disease.

Doctors, scientists and other curious people want to know what is happening inside the body, even at levels that can’t be seen by the naked eye. So far, there is no device small enough to travel through the bloodstream.

If normal machines won’t do the trick, perhaps biology will. Scientists who work in the field of synthetic (合成的) biology are trying to find ways to turn living things into human tools. In the case of the new memory device, bioengineers from Stanford University used the genetic material inside living cells to record information.

This genetic material consists of DNA. Found in nearly every cell, DNA carries all of the information that keeps a living thing alive.

In the new experiment, the researchers turned DNA from bacteria(细菌) into a switch. They “flip (翻转)” a small section of DNA. Then, using the same procedure (过程) , the scientists flip the section again—returning it into its normal structure.

Using these DNA switches, “We can write and erase DNA in a living cell,” bioengineer, Jerome Bonnet, explained to Science News.

It might take years before his team or others identity whether a DNA-based memory device might be practical. Right now, it takes one hour to complete a flip. That is far too long to be useful. Plus, a flipped section has a very small little memory—less than what a computer uses to remember a single letter.

“This was an important proof that it was doable,” Bonnet told Science News. “Now we want to build a more complex system, something that other people can use.”

小题1:What is the aim of listing the electronic things in the first paragraph?

A.To make the passage more fashionable.

B.To show how electronic things have memory.

C.To discuss things in detail.

D.To make the subject of the text more understandable.小题2:What is possible future benefit of the cell-based gadget for people?

A.To detect disease at the earliest point.

B.To help improve the memory.

C.To help people build a body.

D.To replace many electronic gadgets.小题3:What is the object being researched?

A. The cells of bacteria.         

B. The DNA of bacteria.

C. A section of bacteria.         

C. The nucleus of bacteria.

小题4:What do we know about a flipped section of DNA?

A.It has a very small memory.

B.It can function as a computer.

C.It has one letter in it.

D.It takes a day to complete it.

单项选择题