There is a knack in tying ropes together.

把绳子绑在一起有点技巧。

He has a knack of saying funny things.

他有说俏皮话的事。

He has a knack of doing stupid things.

他惯于做蠢事。

Making omelets isn’t difficult, but there’s a knack to it.

做煎蛋饼并不难，但有门。

There is a knack in it.

这里面有点门。