医疗器械的基本质量特性是
A.有效性和适用性
B.经济性和适用性
C.安全性和可靠性
D.可靠性和追溯性
E.安全性和有效性
参考答案:E
It's not wise ______ think you are always right. [ ]
A. of you
B. for you
C. for you to
D. of you to
The famous actor keeps fit and athletic by __________ at the gym for an hour every morning.
A.making out
B.figuring out
C.working out
D.turning out