制备普通琼脂培养基，灭菌宜采用（）
A.煮沸法
B.巴氏消毒法
C.高压蒸气灭菌法
D.流通蒸气灭菌法
E.间歇灭菌法
参考答案：C
1956年，英国心理学家提出短时记忆容量为（）个组块。
A.5～9
B.7～9
C.5～7
D.9～11
Although it was his first experience as chairman, he ______ over the meeting with great skill. A. presided B. administeredC. mastered D. executed
