The father as well as his daughters _____ skating on the freezing river every Sunday afternoon.

A．go

B．goes

C．is going

D．are going

下列曲面的结论中，错误的是（）

A.2x²-3y²-z²＝1表示双叶双曲面

B.2x²+3²-²＝1表示单叶双曲面

C.2x²+3²-²＝1表示椭圆抛物面

D.2（x²+²）-²＝1表示锥面