I feel it is Jack as well as his wife that _______ for their son’s bad performance at school.

A．are to blame

B．is to be blamed

C．are to be blamed

D．is to blame

关于机房工程架空地板，以下哪些说法是正确的？（）

A.机房内可以自由调节气流分布

B.基座架高超过180mm时，应增设防震衍梁

C.应具备良好的静电消除能力

D.地板接地网应采用十字型压接施工方式

E.接地电阻不能大于1欧姆