一定
Meanings
1. surely; certainly; definitely
2. fixed; settled
3. a certain ...; a given ...
Characters used
Examples75
我
Why must I know about it?
我
Why do I have to do that?
如果
You must work hard if you want to succeed.
你
You must pay attention to his advice.
他们
They must be Americans.
他
He must have said so without giving it much thought.