直接致癌物
参考答案：
进入机体后，不需要体内代谢活化，其原型就可与遗传物质作用而诱导细胞癌变的化学致癌物
看一看，数一数，写一写。
例: How many boys are there? Three boys.
1. How many girls are there? ______________________________________
2. How many apples are there? ______________________________________
3. How many dolls are there? ______________________________________
4. How many cars are there? ______________________________________
5. How many dogs are there? ______________________________________
旋压密封式制动缸缸体腐蚀深度大于（）时更换。
A.1mm
B.2mm
C.3mm
D.4mm
