According to this passage, ______ makes some kind of learning difficult.

A．long distance

B．formality

C．much indulgence

D．family influence

水泥粉煤灰碎石桩复合地基具有（）等特点。

A.承载力提高幅度小

B.承载力提高幅度大

C.地基变形小

D.适用范围广

E.地基变形大