have to be是什麼時態

You have to be careful what you say on TV.

在電視上說話時你不得不謹慎。

Bathrooms don't have to be purely functional.

浴室不必完全只爲了實用。

Premature babies have to be fed intravenously.

早產兒必須透過靜脈輸入來餵食。