问题

The flu is believed _____by viruses that like to reproduce in the cells inside the human nose and throat. [ ]

A: causing
B: being caused
C: to be caused
D: to have caused

正确答案是：

同类题型

_Who is _____ English teacher, Lu Yu_ Mr Tian teaches _______ English.

In the room ______ window is wide open ______.

请判断哪一组全是开音节 ______.

________my baseball —It’s under the chair.

I haven’t seen you for a couple of daysWhat have you been up _____? [ ]