问题

How did your brother make such a stupid mistake ______ he had a such a good knowledge of the steps and cautions over operating the machine.[ ]

A:when
B:because
C:while
D:that

正确答案是：

同类题型

下列词语的注音或书写正确的一项是（）

Why does Mr Black look so sad this morning?—I hear that a fire________in his house and lots of valuable things were burned last night.[ ]

I’m looking forward ____________ my parents soon. What about you—Me too.

______ which school was suitable for their son, the parents visited lots of different primary schools in the city.

_____ present, and all ______ goingon smoothly” Said the secretary