So be careful when you answer the knock on your door after dark.
Times, Sunday Times
She later went to the front door, either to answer a knock or to investigate a strange noise outside.
The Sun
She answered my knock by a feeble call from her bed.
Christianity Today
It took several minutes for the bleary-eyed defender to answer their knocks on his door.
The Sun
Answering a knock on the door, she beholds a handsome stranger.
The Times Literary Supplement