焊接铅蓄电池极桩的热源中，以（）获得的修复质量为最佳。
A.交流低压电源
B.汽油焊枪
C.乙炔气焊
参考答案：C
Spelling Bee is a contest _____ competitors, usually children, are asked to spell as many words as possible.
A．which
B．where
C．what
D．when
在口服缓控释制剂中，药物吸收的限速过程为
A．崩解
B．释放
C．吸收
D．代谢
E．不一定
