根据句意及首字母提示完成单词。

1. There are lots of books in the l______.

2. The boys are swimming at the p______.

3. They are s______ at the mall; they want to buy some apples.

4. Listen! The b______ is singing in the tree.

5. Can I use your c______ to take some photos?

木工机械多采用手工送料，容易发生手与刀刃接触，造成伤害。因为木工机械属于( )机械，所以木工机械伤手事故较多。

A．低速
B．中低速
C．中速
D．高速