As if

[Jadoon 84]

How to convert these sentences into past tense?

He plays as if he were a professional. You look as if you knew the knew the secret.

[Rover_KE]

How to convert these sentences into the past tense?

He plays as if he were a professional. You look as if you knew the knew the secret.

Why don't you try first? It's not difficult.

Rover

[Jadoon 84]

Why don't you try first? It's not difficult.

Rover

Respected Teachers
After thinking a lot I am trying as follows. Please check and correct. Thank you very much.
He played as if he had been a professional. You looked as if you had known the secret. ????

[emsr2d2]

Respected Teachers
After thinking a lot I am trying as follows. Please check and correct. Thank you very much.
He played as if he had been a professional. You looked as if you had known the secret. ????

Your answers are OK although the second is quite unlikely. However, depending on the context, backshifting is not obligatory. It's entirely possible that the sentences could read:

He played as if he were a professional.
You looked as if you knew the secret.

[Jadoon 84]

Look at this sentence if it is okay.

You anger as if your cell was broken by me.

Thank you.

[emsr2d2]

We don't use "anger" in this way. It's either a noun, or it's used as a verb in (for example) "It angered me that you thought I was lying" or "He angers his wife on a regular basis". In that context, it means "to make someone else angry".