They were interrupted by a knock at the door.

他们被敲门声打断了。

《牛津词典》

There was a knock at the door.

门外传来敲门声。

youdao

Suddenly there was another knock at the door.

突然，又有人敲门。

youdao

So if you want to taste something good, just knock at the door.

所以如果你想要品尝美味，就都试看吧。

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