问题 选择题

甲、乙两个长方体,由不同材料制成,其中底面积分别为S=40cm2、S=30cm2,高度之比h∶h=3∶2,密度之比为ρ∶ρ=3∶1,若把甲放在水平桌面上,乙放在甲上,水平桌面受到的压强为7000Pa,当把乙取下放在水平桌面上静止不动时,桌面对乙的支持力为 [ ]

A.20N

B.16N

C.9N

D.4N

答案

答案:D

单项选择题
阅读理解

阅读理解。

     I know what you're thinking: pizza (比萨饼)? For breakfast? But the truth is that you can have last

night's leftovers in the a.m. if you want to.

     I know lots of women who skip breakfast (不吃早饭), and they have a ton of different excuses for

doing it. Some say they don't have time, others think they're "saying" calories (卡路里), still others just

don't like breakfast food.

     But the bottom line is that eating in the morning is very important when you're trying to lose weight.

"Eating just about anything from 300 to 400 calories would be better than nothing at all," says Katherine

Brooking, R.D., who developed the super-easy eating plan for this year's "SELF CHALLENGE". And

even pizza can be healthy if it's loaded with vegetables, and you stick to one small piece.

     Breakfast is one meal I never miss, and the same goes for most weight loss success stories. Research

shows that eating breakfast keeps you from overeating later in the day. Researchers at the University of

Southern California found that breakfast skippers have a bigger chance of gaining weight than those who

regularly have a morning meal.

     So eat something in the morning, anything. I know plenty of friends who end up having no breakfast

altogether, and have just coffee or orange juice. I say, try heating up last night's leftovers-it may sound

crazy, but if it works for you, do it! I find if I tell myself, "You can always eat it tomorrow." I put away

the leftovers instead of eating more that night. Try it … you may save yourself some pre-bedtime calories.

And watch your body gain the fat-burning effects.

1. The word "leftovers" in paragraph I probably means _____.

A. food remaining after a meal

B. things left undone

C. meals made of vegetables

D. pizza topped with fruit

2. What can we infer from the text?

A. Working women usually have breakfast in a hurry.

B. Many people have wrong ideas about breakfast.

C. There are some easy ways of cooking a meal.

D. Eating vegetables helps save energy.

3. According to the last paragraph, it is important to ______.

A. eat something for breakfast

B. be careful about what you cat

C. heat up food before eating it

D. cat calorie-controlled food

4. The text is written mainly for those ______.

A. who go to work early

B. who want to lose weight

C. who stay up late

D. who eat before sleep