问题 单项选择题

我国现行的车间空气中有害物质接触限值,应用最广的是

A.最高容许浓度

B.容许接触限值

C.时间加权平均阈限值

D.保障健康的平均职业接触限值

E.上限值

答案

参考答案:A

解析:我国劳动卫生标准《工业企业设计卫生标准》均采用最高容许浓度。

阅读理解

Once upon a time, on an isolated island in the Java sea, lived short people who dominated(支配, 占优势) the food chain. Standing no more than three and a half feet tall, these human ancestors hunted giant rats, lumbering lizards(笨拙的蜥蜴), and miniature elephants.  

It sounds a bit like a fairy tale, but it's true. Unearthed relics on the island uncovered the remains of a race of tiny human ancestors. Homo floresiensis, as the newly discovered species has been named, apparently could date back to 13,000 years ago. This means they have a lot in common with modern humans.

So how and why did these people get so small? Scientists suspect that it's due to the fact that this race lived on an isolated island with limited resources. Take the miniature elephants for example. When elephants first came to the island either by swimming or by some kind of natural land raft, they were probably close to full size. But since there wasn't much to eat, over time smaller elephants lived longer and better. The smaller the elephant was, the less it had to eat to stay strong and healthy.

Scientists call this the "island role", and it can apply to humans as well as animals. Given the island's sparse(稀少) food supply, it makes sense that the early humans living there would have evolved (进化) a body size requiring less food to survive. So bigger isn't always better.

In the floresiensis, at least, getting smaller was the way to go.

小题1:According to the passage, the fact Homo floresiensis are very small is based on________.

A.the islanders in the Java Sea

B.the human ancestors

C.the unearthed relics

D.a newspaper report小题2: The underlined word "miniature" in the first paragraph most probably means______.

A.tiny

B.active

C.rare

D.wild小题3:People on the island got so small because____________.

A.they did not have enough food to eat.

B.they gradually developed for lack of food.

C.they shared less food with elephants.

D.they remained alive as the elephants.小题4: What might be the most suitable title of the passage?

A.The history of short people

B.Short people from a fairy tale

C.The proofs on short people

D.Short people on an isolated island小题5:According to the passage, getting smaller can make people and animals ____

A.run quickly

B.live longer

C.live weaker

D.run slowly

判断题