电动机的额定频率是指输入交流电的频率,我国规定标准电源频率为()。

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问题:

电动机的额定频率是指输入交流电的频率,我国规定标准电源频率为()。

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19世纪三四十年代的英国,经常可以见到这样的现象:衣冠楚楚的绅士和淑女与衣衫褴褛的下层人民同挤一列为车,还得到处给别人让路。保守人士惊呼,铁路会带来某种“平等化的危险”。民主人士则拍手称赞:“我看到这列火车真高兴,我想封建制度是永远一去不复返了。”这主要反映了

A.火车成为陆上主要的交通工具

B.铁路运输导致了封建制度的废除

C.铁路运输消除了社会不平等现象

D.工业革命冲击了传统的社会关系

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简要说明联胺、丙酮在除氧、防腐性能方面的区别。

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WASHINGTON(Reuters)‑People who drink two or more sweetened soft drinks a week have a much higher risk of pancreatic cancer (胰腺癌), an unusual but deadly cancer, researchers reported on Monday.

People who drank mostly fruit juice instead of sodas did not have the same risk, the study of 60,000 people in Singapore found.

“Sugar may be to blame but people who drink sweetened sodas regularly often have other poor health habits,” said Mark Pereira of the University of Minnesota, who led the study.

“The high levels of sugar in soft drinks may be increasing the level of insulin(胰岛素) in the body, which we think contributes to pancreatic cancer cell growth,” President said in a statement.

Writing in the journal Cancer Epidemiology, Biomarkers & Prevention, Pereira and his colleagues said they followed 60,524 men and women in the Singapore—Chinese Health Study for 14 years.

Over that time, 140 of the volunteers developed pancreatic cancer. Those who drank two or more sweetened soft drinks a week had an 87 percent higher risk of being among those who got pancreatic cancer.

Pereira said he believed the findings would apply elsewhere.

“Singapore is a wealthy country with excellent healthcare. Favorite pastimes(消遣) are eating and shopping, so the findings should apply to other western countries.” he said.

But Susan Mayne of the Yale Cancer Center at Yale University in Connecticut was cautious.

“Although this study found a risk, the finding was based on a relatively small number of cases and it remains unclear whether it was a causal(因果的) connection or not.” Said Mayne, who serves on thee board of the journal, which is published by the American Association for Cancer Research.

Pancreatic cancer is one of the deadliest form of cancer, with 230,000 cases globally. In the United States, 37,680 people are diagnosed with pancreatic cancer in a year and 34, 290 die of it.

小题1:We can infer from Pereira’s word that_________

A.the healthcare in Singapore should be greatly improved

B.2 soft drinks a day are considered harmful to health

C.87 out of 140 volunteers developed pancreatic cancer

D.sugar might not be the only cause of pancreatic cancer.小题2:How does Susan seem to feel about the findings of the study?

A.Satisfied

B.Doubtful

C.Worried

D.Hopeful小题3:The best title of the text might be_______

A.The Deadliest Forms of Cancer

B.Drink Fruit Juice Instead of Sodas

C.A Study in University of Minnesota

D.Sugary Soft Drinks Lead to Cancer

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骨骺的损伤常发生在()阶段。

A.婴幼儿

B.儿童少年

C.成年

D.中老年

题型:填空题

洗脸盆的干手器过滤器和洗手液用网格多长时间清洗一次?()

A.15天

B.一个月

C.两个月

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