介导细菌间接合的物质是（）。
A.鞭毛
B.普通菌毛
C.性菌毛
D.中介体
E.核糖体
参考答案：C
—I'm thinking of the test tomorrow. I'm afraid I can't pass this time.
— ! I'm sure you'll make it. [ ]
A. Go ahead
B. Good luck
C. No problem
D. Cheer up
羞怯产生的原因是什么？如何使自己战胜羞怯？
