Find ways to praise your children often,

溶剂的主要作用在于降低成膜物质的黏度，便于施工。( )

混凝工艺有（）阶段。

A.2个

B.3个

C.3个

D.4个

A．(A) Because they want to feel the thrill and excitement.

B．(B) Because they are tired of modern-day university life.

C．(C) Because they are interested in the scientific experiment.

D．(D) Because they find that it is the best way to reduce weight.

乳牙开始萌出的时间是；（）。

A.婴儿出生后5~6个月

B：婴儿出生后7~8个月

C.婴儿出生后10~12个月

D.婴儿出生后14~16个月

天然石材的基本构造方法有：钢筋网固定挂贴法、金属件锚固挂贴法、树脂胶粘结合法、聚脂砂浆固定法和（）等。