根据句子含义，选出画线部分的恰当解释。
1. Now he is black and blue all over.
A. 蓝黑两色
B. 又黑又蓝
C. 又青又紫
D. 脏兮兮的
2. Walls have ears.
A. 隔墙有耳
B. 墙上有洞
C. 墙有耳朵
D. 耳朵有洞
3. It's rains cats and dogs.
A. 下猫下狗
B. 倾盆大雨
C. 毛毛雨
D. 不下雨
4. Mary is the apple of her mother's eye.
A. 妈妈的眼珠
B. 红眼病
C. 眼中钉
D. 掌上明珠
