自动磨边机磨边时噪声很大的原因是：（）。A、镜片安装不正B、镜框接头处有错位或缝隙，

标准状况下, 1体积水吸收560体积氨气所得氨水的密度是0.91g / mL, 该氨水的物质的量浓度约是

A．4 mol / L

B．8 mol / L

C．10 mol /L

D．16 mol / L

It seems like every day there's some new research about whether our favorite drinks are good for us.  One day,  science says a glass of red wine a day will help us live longer. The next day, maybe not.  It seems journalists are pretty interested in wine research and the same might be said for coffee.  Now there's been a lot of research into whether coffee's good for our health "the results have really been mixed"，admits Neal Freedman who led the coffee study and published his findings in a medical journal recently.   "There's been some evidence that coffee might increase the risk of certain diseases and there's also  been  maybe  more recent evidence that coffee  may protect against other diseases as well".

Freedman and his colleagues undertook the biggest study yet to look at the relationship between coffee and health.  They analyzed data collected from  more than  400，000 Americans ages 50 to 70 participating in the study.  "We found that the coffee drinkers had a modestly lower risk of death than the non-drinkers， he said.  Here's what he means by "modestly": those who drank at least two or three cups a day were about 10 percent or 15 percent less likely to die for any reason during the 13 years of the study when the researchers looked at specific causes of death, coffee drinking appeared to cut the  risk  of  dying from  heart  disease, lung  disease injuries,  accidents  and infections.

Now, Freedman stressed that the study doesn't prove coffee can make people live longer .A study like this can never prove a cause-and-effect relationship.  All it can really do is to point researchers in the right direction for further investigation. And even if it turns out that coffee is really good for you, scientists have no idea why.

小题1:According to the first paragraph，reporters  would like to  know  the research findings of_______.

A． tea

B． beer

C． coffee

D． wine小题2:According to the passage, which of the following is TRUE?

A． Freedman and his colleagues hired 400，000 Americans to collect date.

B． People who took part in Freedman's research are about 50 to 70 years old.

C． About 400, 000 Americans worked for Freedman's team for 13 years.

D． People who are 50 to 70 years old seldom drink wffee.小题3:According to the author, scientists________.

A． have already proved that coffee is good for human health

B． have a long way to go before they find a way to study coffee

C． have avoided the cause-and-effect approach to study coffee

D． are still unable to figure out why coffee is good for us小题4:Which of the following can be the best title?

A． The Magical Effects of Coffee

B． Neal Freedman and His Research

C． Can Coffee Help You Live Longer?

D． A Cup of Coffee A Day Makes Diseases Away

赵孟頫的妻子（）也是著名书画家。

A.卫夫人

B.管道升

C.蔡文姬

D.谢道韫

电弧电压主要影响( )。

A．熔深

B．单道焊缝厚度

C．余高

D．单道焊缝宽度

污水处理厂的其他构筑物和设施都是围绕（）设置的。

A.初次沉淀池

B.曝气池

C.二次沉淀池

D.污泥回收系统