Can you please check these sentences?

I just need to know if they are ok.

1) When do you usually get off work?
He took a day off work to drive me to the airport.
2) The manager has just laid off Peter’s father.
Can you put me through to the manager, please?
He has taken on new farm labourers for the grape harvest.
4) When do you think you'll come back to work? When do you think of coming back to work?
Our teacher takes off a mark for each/every (is possible) grammar mistake.
5) Would you mind if I turned down the volume on the radio?
If Peter had turned down the gas, he wouldn’t have burned/burnt the dinner.
6) Cold days bring on my cough.
The teapot came apart in my hands and I burned/scalded myself.
Some students are taken on for fruit-picking in the summer.

All are fine except for a couple of things in #4.

First sentence - fine.
Second sentence - When are you thinking of coming back to work?
Third sentence - yes, both pronouns are possible.