填石渗沟需要用较大碎石或卵石填筑的部位有（）。A.边部 B.底部 C.上部 D.中间

“USA? Britain? Which country is better to study in?” We often hear such discussions. As China open its door, it is a dream for many Chinese students to study abroad. They want to learn about the outside world.
It’s true that studying abroad can help students develop themselves. Their foreign language skills will be improved and it may be easier to find jobs.
But there are problems that should be considered. Language is the first. Students must spend a lot of time learning another language.
Students must also learn to live without parents’ care and deal with all kinds of things they haven’t to do before, like looking after themselves. There are reports about Chineses students abroad running into an ocean of difficulties and giving up finally. When they have to take care of themselves, it is hard for students to study well.
Finally, studying abroad brings a heavy burden to the family. For most Chinese parents, the cost of studying abroad is very high. But is it worth it?
We know that there are many famous people who have achieved success through their hard work in China. Liu Xiang is a good example. Once an American teacher invited him there, but he refused. He kept training hard with his Chinese teacher. He surprised the world when he won a gold medal at the Athens Olympic Games. So when you winder which country is better to study in, think it again.

Title: Studying at home or abroad.
Phenomenon（现象）	Studying abroad has become a     小题1:   for Chinese students.
Advantages	* It is helpful to the future development for Chinese students.
	* It helps to improve foreign language skills.
	* It enables Chinese students to find jobs easily.
小题2:   .	* It takes Chinese students too much time to learn a foreign language.
	* It’s hard for Chinese students to be used to the life abroad without. parents’ care.
	* Parents may be under pressure(压力) because the cost of studying abroad is very    小题3:   .
Purpose: To tell us studying abroad is not the only way to be  小题4:by describing Liu Xiang’s example.