在生物的演化历史中总共有四次公认的大规模灭绝事件，每次灭绝事件均标志着一个地质时代的结束和另一个地质时代的开始。

e cmell the wy to Chin for lerning it better ______ for mking money.other thn B．more thn C．better thn D．rther thnA．other thanB．more thanC．better thanD．rather than

hild, sheMrs. Ball has a son. His name is Mick. She _ _1_ _ him very much and as he is not a __ 2 __ child, she is always _ _3_ _ that he may be ill, _ _4_ _ she takes him to see the best _ _5_ _ in the town four times a year and the doctor always looks him over_ _6__ . During one of these __ 7_ _, the doctor gives Mick all kinds of tests and then says to him, “Do you have any _ _8_ _ with your nose or ears these days ” Mick _ _9_ _ for a second and then answers, “Yes, I __ 10_ _.” Mrs. Ball is very _ _11_ _. “But I’m sure you don’t tell me about__12__, Mick!” She says worriedly. “Oh, really ” Says the doctor seriously（） B．nose C．mouth D．ear