根据句意，用所给单词的适当形式填空。

1. Look, there is a bird _____ (sing) in the tree.

2. The bad air makes my chest hurt and it's difficult for me _____ (breath).

3. They are doing their homework carefully. You'd better not _____ (disturb) them.

4. Litter _____ (influence) the look of our city.

5. It is known that smoking does great _____ (harm) to us.

钢筋弯曲量度差值是指（）。

A、外包尺寸与内包尺寸间差值

B、外包尺寸与轴线间差值

C、轴线与内包尺寸间差值

D、外包尺寸与中心线长度间差值