问题

o Chinese scientists have made a wonderfuldiscovery, which marks a major _______ in the basic research in the field.

A:reform
B:approach
C:boundary
D:breakthrough

正确答案是：

同类题型

ot in the shopping mall, because the air-conditioningsystem ______.

Due to the widespread ________ of this medical technology, more diseases can be discovered and treated at an early stage.

I saw him crossing the street. The sentence structure is _______.

You _________ such clothes because you are still astudent.

1Finally, tired happy,we took the subway back home.