At that second knock, a window on the third floor opened and the same Snail looked out.

第二次敲门时，三楼的一扇窗户打开了，还是那只蜗牛往外看。

youdao

At that point there was a light knock on the door.

就在这时，有人轻轻地敲门。

youdao

At that moment there came a tolerably violent knock on the door.

这时，有人在门上敲了一下，并且敲得相当凶。

youdao

He said there was a knock on the door at about 18:30 GMT.

BBC: Graffiti on path

Consultants have told the BBC there are also concerns over staffing the emergency department, covering holiday and sick leave, and the fact that the rest of the hospital system does not follow a seven-day working pattern shift, which has a knock on effect especially at the weekends.

BBC: Northern Ireland

Such restrictions can have knock-on effects that work at odds with Manila's other economic goals.

WSJ: Business Asia: Investing: It's More Frustrating in the Philippines