问题

The scientists will succeed in their experiment______ they give up.

A:unless
B:if
C:after
D:until;

正确答案是：

同类题型

Where do you live ____ —I live ____a flat.

A: Is your father a teacherB: Yes, he is. He ______ at a high school.

All the students are working hard now.—_______. Because all of them want to go to goodcolleges.

Everybody likes to keep_______.

－Let’s go swimming, Linda.－It sounds good, I’m too busy.