问题 填空题

草坪式浴室防滑垫是由柔软的PVC材料制成,其正面为仿草坪式设计串利于增大摩擦,背面有许多小吸盘(如图所示)。当人站在正面时,脚对地面的压力与地面对脚的支持力是—对______力,背面则是利用______产生的较大压力来增大垫与地之间的摩擦力,从而达到理想的防滑效果。

答案

相互作用,大气压强

当人站在正面时,脚对地面的压力与地面对脚的支持力是—对相互作用力,根据防滑垫的设计特点,可以看出它的有吸盘的一面是为了利用大气压将防滑垫紧压在瓷砖上,防止瓷砖滑动的。

阅读理解

第三部分:阅读理解(共20小题,每题2分)

Bamboo (竹子) is one of nature’s (自然) most surprising plants. Many people call this plant a tree, but it is a kind of grass.

Like other kinds of grass, a bamboo plant may be cut very low to the ground, but it will grow back very quickly. A Japanese scientist reported one bamboo plant which grew 1.5 meters (4 feet) in 24 hours! Bamboo grows almost everywhere in the world except Europe. There are more than 1, 000 kinds of bamboo.

Not all bamboo looks the same. Some bamboo plants are very thin. They may only grow to be a few centimeters wide while others may grow to more than 30 centimeters (1 foot) across. This plant also comes in different colors, from yellow to black to green.

Bamboo has been used to make many things such as hats and kitchen tools(厨房用具). Because it is strong, bamboo is also used to build buildings.

Many Asian countries have used bamboo for hundreds of years. They often use bamboo for buildings and supporting (支撑) new buildings and bridges while they are being built.

In Africa, poor farmers are taught how to find water using bamboo. These African countries need cheap way to find water because they have no money, and their fields often die from no rain and no water.Bamboo pipes (管子) help poor farmers bring water to their thirsty fields without spending a lot of money.

1.How is bamboo like grass?

A.It grows quickly. B.It’s wood.    C.it is easy to cut.  D.It is very thin.

2.Though you can see bamboo everywhere, it doesn’t grow      .

A.in China      B.in Europe C.on mountains   D.in Africa

2.Why is bamboo used by African poor farmers? Because       .

A.it is cheap B.it has different colors  C.it is strong   D.it has been used by Asians

3.In Asia, bamboo has been used for     .

A.a short time                    B.many thousands of years

C.many hundreds of years          D.about 100 years

单项选择题