下列表示物质结构的化学用语或模型正确的是( )
A.8个中子的氧原子的核素符号:168O
B.HF的电子式:
C.K+离子的结构示意图:
D.CH4分子的球棍模型:
答案:A
If you do not know how to say something in English, you say: _____. [ ]
A. I don't know.
B. Excuse me. How do you say that in English?
C. I will start now.
D. I'm sorry. I don't know.
避免颅内压突然增高的措施有()
A.保持呼吸通畅
B.保持大便通畅
C.控制咳嗽
D.控制癫痫发作
E.妥善保护,加以约束