The secretary is very careful and never ___ any little points in her daily work.

A．overcomes

B．overlooks

C．refuses

D．denies

通常必须对柴油机冷却水进行处理的原因是（）。

A.冷却水呈碱性

B.冷却水呈酸性

C.冷却水含盐类

D.冷却水含杂质