— I phoned you at about three this afternoon, but no one answered.

— Oh, that was probably _______ I was doing exercise outdoors.

A．when

B．why

C．what

D．that

人体感染旋毛虫的主要原因是（）.

A.生食或半生食鱼肉

B.生食或半生食虾

C.生食或半生食猪肉

D.生食或半生食蛙肉

E.生食或半生食蔬菜