3．下列条件中，不能判定△ABC是等腰三角形的是（ ）

A．a∶b∶c＝2∶3∶4

B．a＝3，b＝4，c＝3

C．∠B＝50º，∠C＝80º

D．∠A∶∠B∶∠C＝1∶1∶2

用所给词的正确形式填空。

1. Chicago is _____ (big) than Paris.

2. This book is_____ (good) than that one.

3. The weather this winter is _____ (bad) than the weather last winter.

4. He is a little _____ (young) than me.

5. Mr Smith is much _____ (old) than his wife.