栓剂的水溶性基质（）
A.PVA
B.聚丙烯酸树脂
C.PVP
D.PEG
E.乙基纤维素
参考答案：D
Mr. Tong asked us ____ be afraid of ____ the exam. [ ]
A. to; have
B. not to; have
C. to; having
D. not to; having
KL4001的输出信号范围是（）.
A.-10V～10V
B.0V～10V
C.4mA～20mA
D.0mA～20mA
