维持电弧稳定燃烧主要依靠（）。
A.碰撞游离；
B.热游离；
C.去游离；
D.强电场发射。
参考答案：B
用适当的介词填空。
1. There is a bank _____ from the park..
2. Go _____ Center Street and you can find the supermarket _____ the left.
3. Is there a hotel _____ the neighborhood
4. The bookstore is _____ the hotel and the park.
5. Xinhua Bookstore is _____ Fifth Avenue.
