为了保证注射用水的质量,一般要求可在无菌条件下保存的时间是()
A.14h以内
B.12h以内
C.15h以内
D.18h以内
E.20h以内
参考答案:B
膈下肋骨前后位摄影时,采取的呼吸方式为()
A.深呼气后屏住呼吸
B.深吸气后屏住呼吸
C.自由呼吸
D.均匀连续呼吸
E.快呼快吸
The students asked _________________.
A.when can they surf the Internet in class
B.when could they surf the Internet in class
C.when they could surf the Internet in class
D.when they can surf the Internet in class