问题

The problem will appear _______ a different welfare system will be created.[ ]
A: unless
B: whether
C: until
D: if
B: whether
C: until
D: if
正确答案是:
同类题型
Our teacher told us that we must be strict ourselvesour study.
Whose sweater is that— It _______ be Tim’s. It’s _______ big for him.
– The lecture will begin at 4 o’clock in the afternoon, right?– Yeah, ____ you get there on time.
The food here is nice enough.—My friend ______ me a right place[ ]
Our English teacher ______ a computer ______ teach us this text.