问题
The air pollution is terrible.–It will be worse_______ we take action to protect the environment.
A:if
B:unless
C:until
D:when;
B:unless
C:until
D:when;
正确答案是：
同类题型
A tourist will easily lose his way in Shanghai_____ hehas a map or a guide.
_______ it got dark, they didn’t stop working.
_____ does he live from our school— About thirty minutes’ walk.
Could you meet me at the airport—I’d like to，but I ________Shanghai when you return.
________you have soccer balls—Yes, I do. And I have two baseballs.