His letter was so confusing that I could hardly make any ______ of it.

A．explanation

B．meaning

C．sense

D．guess

土工格栅、土工网网孔测定，对于较规则的三角形网孔面积计算公式是（）。

A.A=0.8860h2

B.A=0.7265h2

C.A=hxhy

D.A=0.5774h2