We should make full use of whatever happens to us．There is always____ to learn from every experience.

A．nothing

B．anything

C．something

D．everything

既能改善混凝土拌和物流变性能，又能改善混凝土耐久性的外加剂是( )。

A．引气剂

B．泵送剂

C．减水剂

D．着色剂