有人在敲門。

Someone's knocking at the door.

Source: Tatoeba

Sentence Composition

1 有人 yǒurén
  1. someone
  2. people
  3. anyone
  4. there is someone there
  5. occupied (as in restroom)
2 在 zài
  1. to exist; to be alive
  2. (of sb or sth) to be (located) at
  3. (used before a verb to indicate an action in progress)
3 敲門 qiāomén to knock on a door