用所给词的适当形式填空。

     I'm Carol. Do you know how I study English? Well, vocabulary is the 1.________ (important) thing for me to study.  I always listen to the English program on the radio. When I hear some new words, I try 2.        (keep) them in my mind. Then after one or 3. ______(twice) days, I still remember some of them. I don't learn English just from English lessons. I learn it in 4.______ (difference) ways. Of course, I read some 5.        (interest) stories in English. I also speak a lot. To speak to myself is a good way. Many people don't like to do that. But I like doing that.

主通风机安全运行中下列说法正确的是（）

A.运转中要经常注意主通风机的声音和振动，若有异常情况，应停机检查

B.若发现叶轮和机壳内壁有摩擦声，必须停机检查

C.必要时可采用局部通风机作为主通风机使用

D.需经常保证润滑系统油的质量和油量