28. Our schoolmaster tried his best to make our teaching methods _____ to the concerning parents at the press, who are eager to send their child to our school.

A．get through

B．get across

C．get over

D．get around

干混砂浆由（）材料组成。

A.水泥

B.细骨料

C.矿物掺合料

D.干燥骨料或粉料

E.添加剂