Bang, bash, belt, bump, criticize, damn, ping, rap, roast, smash, sock, strike, tap, and whack are synonyms for knock.
overall
Substances would work
I started to knock on the door. I will knock before I open the door.
It depends what kind of cold you are asking about. I would recommend searching a thesaurus: thesaurus.com is a place you could look.
2
Some alternative words to use instead of "he" include: they, it, the person, the individual, one.
you can use or , otherwise, or rather than.
Some words to use instead of got are Get, Gotten, Getten, have, had!
Was the joke this instead? Knock, Knock! Who's there? Hop. Hop who? Hop, Hop, Away. - The Easter Bunny's gone!
instead of knock on wood, it can be knock on snow!
like
traitor
a or an
Instead of the phrase "freaked out", try:stunnedstartledalarmedpanicked
Alternative words to use instead of "fake" could be artificial, counterfeit, synthetic, or imitation.
You could use words like us, we, our, ourselves.
If one chooses to use figures instead of words in a sentence/paragraph one must be consistent. That is use ONLY figures or ONLY words and do not mix them both.