排气系统主要由以下主要部件组成，排气管装有三元催化器（）。
A.排气歧管
B.排气管
C.消声器
D.密封件
参考答案：A, B, C, D
写出下列句子的同义句。
1. This is my book. → The book is .
2. What's the name of your city? → What's your name?
3. I always go to school on foot. → I always to school.
4. What's your age (年龄)? → are you?
5. It's time for breakfast. → It's time breakfast.
