问题

If you keep on working hard, I have no doubt ___ you’ll be successful in the future.
A:whether
B:when
C:that
D:if;
B:when
C:that
D:if;
正确答案是:
同类题型
Though Jim bought his wife a set of combs, ___ it was of no use
ould you lend me a few dollars until I ______ atthe end of this month
’t see your sister at the cinema. Ifshe ______, she would have met my brother.
______does your mother go shopping —About once a week.
What’s the weather like today—- It’s ________ warm ________ yesterday.