问题
单项选择题
直动式减压阀属于()
A.精密减压阀
B.普通减压阀
C.高精度减压阀
D.快速减压阀
答案
参考答案:B
直动式减压阀属于()
A.精密减压阀
B.普通减压阀
C.高精度减压阀
D.快速减压阀
参考答案:B
选词填空。 | |
2. There _____ to be a lot of manatees. 3. Some of the swamps have become _____. 4. I feel that zoos _____ clean and safe places for _____ animals to live and help to _____ the public about _____ for them. |