在模拟通信系统中信噪比越低说明通信质量（）。
A、越差
B、越好
C、无关
参考答案：A
猪瘟弱毒冻干苗需要在（）条件下保存。
A、常温
B、-4℃
C、-15℃
— ________.
— He's a doctor. [ ]
A. What does he like?
B. Where does he work?
C. What does he do?
D. What does he look like?
