Question

    Do you know viruses (病毒) and bacteria (细菌)? Both of them are very small, we can't see them with our eyes, and many people know nothing about them, In fact, there are a number of differences between viruses and bacteria. Bacterium, the singular form of the word bacteria, is a one-celled (单细胞) living thing, with complete sets of both RNA and DNA genetic codes (遗传密码). For viruses, some are sections of RNA, and the others are sections of DNA. So, bacterium is at least a hundred times larger than a typical virus.

One main difference between viruses and bacteria is the method of reproduction. A bacterium is a completely independent and self-reproducing unit. When the time is right, bacterium will divide its DNA and RNA genetic material in two. This is how bacteria live in almost every environment on Earth, including non-living things like rocks or plastic.

A virus, on the other hand, cannot reproduce without a living host. A virus may lie for thousands of years before finally coming into a suitable host. Once it enters the body of a host, a virus will get in the ling cell. Once inside a living cell, a virus takes the place of the living cell's DNA or RNA genetic instructions with its own. Those instructions are usually to make as many copies of the virus as possible.

Ninety-nine percent of all known bacteria are considered useful to humans, or at least have no bad influence. But most viruses, on the other hand, serve no good purpose. Their only purpose is to create more viruses in order to make themselves continue to live.

Bacteria are alive, which means they can be killed by some form of chemical things. Antibiotics (抗生素) can kill bacteria. Viruses, by comparison, are not considered living things. They cannot be 'killed' in the same way as antibiotics kill bacteria. In fact, any medicine is useless for virus' infections. The disease must run its course until the body can make a successful protection on its own.

Viruses and Bacteria
Similarity	Both are too small 1. with our eyes.
Differences		Viruses	Bacteria
What they're like	● They are not living things.	● They are living things.
● A virus is a section of 2. RNA 3. DNA.	● A bacterium has complete sets of both RNA and DNA genetic codes.
● A virus is much smaller than a bacterium.
How they reproduce	A virus can not copy without a living host	A bacterium can reproduce 4. in almost every environment on Earth.
How they influence humans	Most of them do 5.humans.	Most of them are considered useful to humans, or at least have no bad influence.
6.for viruses and bacteria	We can use antibiotics to kill bacteria while for viruses it only depends on if our body can make a successful protection on its own.

Answer

1.to see

2.either

3.or

4.genetic material

5.something bad for

6.Prevention

【解析】

本文是一篇说明文，主要介绍了病毒和细菌之间的相同点和差别。

1.细节理解题。根据第1大段“Both of them are very small, we can't see them with our eyes,”它们都很小，我们眼睛看不到。联系题干的意思是太小了而眼睛看不到，too…to太……而不能；太小了而看不到，see。故答案填to see。

2.细节理解题。根据第1大段“For viruses, some are sections of RNA, and the others are sections of DNA.”对于病毒来说，有些是RNA片段，有些是DNA片段。可知，病毒要么是RNA片段，要么是DNA片段。要么……要么either…or。故答案填either。

3.细节理解题。根据第1大段“For viruses, some are sections of RNA, and the others are sections of DNA.”对于病毒来说，有些是RNA片段，有些是DNA片段。可知，病毒要么是RNA片段，要么是DNA片段。要么……要么either…or。故答案填or。

4.细节理解题。根据第2大段“When the time is right, bacterium will divide its DNA and RNA genetic material in two.”当时机成熟时，细菌会将其DNA和RNA遗传物质一分为二。可知，细菌会繁衍遗传物质。故答案填genetic material。

5.细节理解题。根据第4大段“But most viruses, on the other hand, serve no good purpose.”但是另一方面，大部分的病毒没有什么好用途。可知，对人类是有害的。故答案填something bad for。

6.推理判断题。联系右边表格信息“We can use antibiotics to kill bacteria while for viruses it only depends on if our body can make a successful protection on its own.”我们可以使用抗生素来杀死细菌，而对于病毒来说，这只取决于我们的身体是否能成功地自我保护。可知，这是对病毒和细菌的防范，prevention名词预防。故答案填Prevention。