用如图所示的滑轮组匀速提升600N的重物时，人手实际需提供的拉力应该是（ ）

任务型阅读。根据短文内容，回答问题。

Do you often have a cold, headache or backache? If your answer is yes, your health is a problem. Healthy foods are good for our health. Tofu is a kind of healthy food. It is also a traditional Chinese food. We often eat it in China. Now, many people in other countries think tofu is good for health, too. They also like eating it.

Milk is another kind of healthy food. You should drink one or two glasses of milk every day.

Vegetables are important, too. You should eat lots of them. There are vitamin A, B, C, D, E (维生素A,B,C,D,E) and other vitamins in them.

Of course, it’s important to eat a balanced diet. You need some pork, chicken or beef every day. But you shouldn’t eat much of them.

小题1:Are healthy foods good for your health?

小题2:What’s the traditional food in China?

小题3:Why are vegetables important to our health?

小题4:Which is a good diet: some beef, some pork, a hamburger and a glass of cola for dinner or some pork, tofu and some vegetables?

小题5:What did you have for dinner last night?

在△ABC中，三个内角分别是A，B，C，若sinC=2cosAsinB。则此△ABC一定是（ ）

A．直角三角形          B.正三角形           C。等腰三角形      D.等腰直角三角形

应立卷归档的公文是（）。

A．具有查考价值的已处理完毕的公文

B．明令撤销的公文

C．秘密公文

D．未经本人审阅的领导人讲话稿

理气药性多辛温香燥，慎用于（）

A.气虚证

B.血虚证

C.气阴不足证

D.阴虚证

E.气滞血瘀证

肾性水肿一般首先表现出（）

A．双下肢对称性可凹性水肿

B．胸腔积液

C．心包积液

D．腹水

E．眼睑及面部水肿