电工用玻璃按其用途可分为绝缘子玻璃、电真空玻璃、（）和低熔点玻璃等。

圣诞树用成套灯具

如图所示，甲、乙两个实心圆柱体放在水平地面上，它们对地面的压强相等，则下列判断正确的是：

A.甲的密度大

B.甲的密度小

C.甲受到的重力小

D.甲受到的重力大

有机固体废物的好氧堆制可人为的划分为几个时期？都有哪些微生物参与？

阅读理解。

    In Canada you can find dogs, cats, horses, etc. in almost every family. These are their pets. People love

these pets and have them as their good friends. Before they keep them in their houses, they take them to

animal hospitals to give them injections (注射) so that they won't carry diseases. They have special animal

food stores, though they can get animal food in almost every kind of stores. Some people spend around two

hundred Canadian dollars a month on animal food.

    When you visit people's houses, they would be very glad to show you their pets and they are very proud

of them. You will also find that almost every family has a bird feeder in their garden. All kinds of birds are

welcomed to come and have a good meal. They are free to come and go and nobody is allowed to kill any

animal in Canada. They have a law against killing wild animals. If you killed an animal, you would be punished.

If an animal happened to get run over by a car, people would be very sad about it.

    People in Canada have many reasons to like animals. One of them might be: Their family ties are not as

close as ours. When children grow up, they leave their parents and start their own life. Then the old will feel

lonely. But pets can solve this problem. They can be good friends and never leave them alone.

1. The passage mainly talks about _____.

A. how to keep disease from pets

B. pets in Canada

C. how to take good care of pets

D. life of the old in Canada

2. They give their pets injections before keeping them at their houses because _____.

A. the pets are sick

B. the pets are wild

C. they want to stop them from carrying disease

D. they want them to sleep on the way home

3. In Canada, children leave their parents when they grow up because _____.

A. they don't love their parents any more

B. they can only find jobs far from their parents

C. their parents' houses are too small

D. they wouldn't depend on their parents any more

4. Which of the following is TRUE? 　　

A. People buy animal food only at the animal food stores. 　

B. Pets eat better than people. 　　

C. Almost every family has a birdcage in his house. 　　

D. Any bird can come to the bird feeders to eat.

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