Just before the Chinese class, I suddenly realized that I forgot _______ my Chinese text book.

A．bring

B．bringing

C．and bring

D．to bring

有4个不同的球，4个不同的盒子，现在要把球全部放入盒内．

(1)共有几种放法？

(2)恰有一个盒不放球，共有几种放法？