知道该怎么

know how to

→ 知道
phrase Uncommon #7,119
know how to Often followed by a verb; in negative sentences, 不知道该怎么 means “not know how to.”
CH: 我知道该怎么回答这个问题。
EN: I know how to answer this question.

等你知道该怎么爱一个人而不是编谎话来找我

Come back to me when you know how to love someone instead of making up lies.

— 朱诺 (2007)

你也知道该怎么砍断绳索吧?

You know how to cut through the ropes too, right?

— 西部往事 (1968)