差动放大器零漂大小与（）有关。
A.电路的对称性
B.恒流源的性能
C.温度的高低
D.负载的轻重
参考答案：A, B, C
The police_________the thief at this time the day before yesterday. [ ]
A. were catching
B. are catching
C. was catching
D. is catching
五味子的主产地区是（）
A.华东
B.华南
C.西南
D.西北
E.东北
