检验气缸体有无裂纹的方法，通常采用（）。
A.敲击法
B.磁力探伤法
C.水压试验法
参考答案：C
句型转换。
1. Why don't you ask Tom for help?(改为同义句)
_____ _____ ask Tom for help?
2. Have you got any pen friends?(改为同义句)
_____ you _____ any pen friends?
3. Don't forget to speak English, _____ _____?(完成反意疑问句)
4. To remember new words is difficult.(改为同义句)
_____ difficult _____ remember new words.
5. I was born in Tianjin in 1991.(对画线部分提问)
_____ and _____ _____ you born?
其他酰脲及其衍生物以及它们的盐
