Definition
to be necessary or compelled to do something.
必須
I have to travel to San Francisco for business tomorrow.
我明天必須去舊金山出差。
What time do you have to arrive there?
你必須什麼時候到達那裡？
Is it necessary that we complete this today?
我們有必要今天完成這件事嗎？
used to indicate something is very likely to be true.
必定是真的；很可能是真的
That total must be correct; I’ve already verified it twice.
那個總數一定是正確的；我已經核對過兩次了。
That jacket is very gaudy; it has to be Jude's.
那件外套很花哨；一定是Jude的。
We were sure her house had to be located somewhere nearby.
我們確定她的房子一定在附近某個地方。
to be necessary or compelled to do something.
必須
I have to travel to San Francisco for business tomorrow.
我明天必須去舊金山出差。
What time do you have to arrive there?
你必須幾點到那裡？
Is it necessary that we complete this today?
我們有必要今天完成這件事嗎？
used to indicate something is very likely to be true.
必定是真的；很可能是真的
That total must be correct; I’ve already verified it twice.
那個總數一定是正確的；我已經核對過兩次了。
That jacket is very gaudy; it has to be Jude's.
那件外套非常花俏；一定是裘德的。
We were sure her house had to be located somewhere nearby.
我們確信她的房子一定就在附近某處。