微生物学初创时期的代表人物是（）。
A.巴斯德
B.科赫
C.列文·虎克
D.维诺格拉德斯基
参考答案：C
已知圆的周长为50，用含π的代数式表示圆的半径，应是______．
David apologized to me yesterday. __, I won't forgive him for it was not the first time that he had hurt me.
A．If so
B．If ever
C．Even so
D．Even though
