在压力表的型号表示中，第一个字母Y、Z、YZ分别表示什么？
参考答案：
分别表示压力表、真空表和压力真空表。
用所给词的适当形式填空。
1.They are trying to do something _____ (help) the old.
2. If at first you don't _____ (success) ,try,try again.
3. My cousin is used to _____ (study) with his new friends in Australia.
4. If Simon _____ (have) time next weekend,he will go to the zoo.
侧颅底肿瘤的手术切除进路主要有__________和__________。
