为使构件在对称循环交变应力下正常工作，构件内的最大应力应小于或等于（）。 A.材料的

急性再生障碍性贫血的骨髓增生程度大多呈（）

A.极度活跃

B.明显活跃

C.增生活跃

D.极度减低

E.增生极度减低

* * 党员如果敢于坚持真理，那么，必须同歪风邪气进行针锋相对的斗争；如果对错误的东西一味顺着、跟着、护着，那么只能助长不正之风的恶性蔓延。所以( )。

A．搞不正之风的人中没有 * * 党员

B．只有 * * 党员才对不正之风进行针锋相对的斗争

C．敢于坚持真理的 * * 党员必定对歪风邪气进行针锋相对的斗争

D．所有的 * * 党员都对歪风邪气进行针锋相对的斗争

有关CM代谢叙述错误的是 （）

A.外源性TG可与胆固醇、磷脂、ApoAⅣ、ApoB48结合形成CM

B.进入血液中的CM可以从LDL接受ApoCⅡ、ApoE及胆固醇酯

C.毛细血管内的LPL被ApoCⅡ活化，水解CM中的TG

D.CM残粒以ApoB48和ApoE为主

E.CM在血液中的半衰期为5～15分钟

阅读理解

     A recent study of ancient and modern elephants has come up with the unexpected conclusion

that the African elephant is divided into two distinct (不同的) species.

     The discovery was made by researchers at York and Harvard Universities when they were

examining the genetic relationship between the ancient woolly mammoth and mastodon to

modern elephants-the Asian elephant, African forest elephant,and African savanna elephant.

Once they obtained DNA sequences (序列) from two fossils (化石), mammoths and mastodons,

the team compared them with DNA from modern elephants.They found to their amazement that modern forest and savanna elephants are as distinct from each other as Asian elephants and

mammoths.

     The scientists used detailed genetic analysis to prove that the African savanna elephant and

the African forest elephant have been distinct species for several million years.The divergence

of the two species took place around the time of the divergence of Asian elephants and woolly

mammoths.This result amazed all the scientists.

     There has long been debate in the scientific community that the two might be separate

species, but this is the most convincing scientific evidence so far that they are indeed different

species.

     Previously, many naturalists believed that African savanna elephants and African forest

elephants were two populations of the same species, despite the elephants' significant size

differences.The savanna elephant has an average shoulder height of 3.5 metres while the forest elephant has an average shoulder height of 2.5 metres.The savanna elephant weighs between six and seven tons, roughly double the weight of the forest elephant.But the fact that they look so

different does not necessarily mean they are different species.However the proof lay in the

analysis of the DNA.

     Alfred Roca, assistant professor in the Department of Animal Sciences at the University of

Illinois, said, "We now have to treat the forest and savanna elephants as two different units for

conservation purposes.Since 1950, all African elephants have been conserved as one species.

Now that we know the forest and savanna elephants are two very distinctive animals, the forest elephant should become a bigger priority(优先) for conservation purposes."

1. One of the fossils studied by the researchers is that of________.

A. the Asian elephant            

B. the forest elephant

C. the savanna elephant          

D. the mastodon elephant

2. The underlined word"divergence" in Paragraph 4 means "________"．

A. evolution              

B. exhibition

C. separation            

D. examination

3. The researchers' conclusion was based on a study of the African elephant's________.

A. DNA            

B. height

C. weight          

D. population

4. What are Alfred Roca's words mainly about?  

A. The conservation of African elephants.

B. The purpose of studying African elephants.

C. The way to divide African elephants into two units.

D. The reason for the distinction of African elephants.