— Must I turn off the gas after cooking?— Of course. You can never be________ careful with that.
– Which is the best way ____ to school?-- By bus.
It usually ____ him fifteen minutes to walk to school.
____ students get up at six and ____ get up at six thirty.
I think you can ____ to the new park. It’s a little far.
I don’t know____. Can you tell me?