29．What has been studied suggest that a short nap in the afternoon_______yourefreshed for the next four or five hours.

Mr Huang told us to spend as much time as possible ________ our English studies. [ ]

It____have been Tom that parked the car here, as he is the only one with a car.[ ]

I have a lot of homework to do today, _________ I cannot go swimming with you.

You should practice reading as much as you can, since it is a(n) ______ skill, and it must be taken seriously.