I'm not sure whether I should tell you this.
我拿不准该不该把这事告诉你。
She asked her boss whether she could have the day off.
她问老板可不可以让她请一天假。
You've got to go to school, whether you like it or not.
不管你喜欢不喜欢，你得上学。
It's doubtful whether the car will last another year.
这辆汽车未必还能用上一年。
It remains to be seen whether his project will fly.
他的计划能否成功尚需拭目以待。