YOU SAID:

Who's knocking on my door?

INTO JAPANESE

私のドアをたたくのですか。

BACK INTO ENGLISH

Is knocking on my door?

INTO JAPANESE

私のドアをノックしていますか。

BACK INTO ENGLISH

Is knocking at my door?

INTO JAPANESE

私のドアをノックしていますか?

BACK INTO ENGLISH

You are knocking at my door?

INTO JAPANESE

あなたが私のドアをノックして?

BACK INTO ENGLISH

You are knocking at my door?