—I didn’t expect that John would be absent from my last Sunday’s birthday party.—As far as I know, he ______ to see his parents in the countryside on Sundays.
Time should be made good use ______ out lessons well.
.Which do you enjoy ______ your weekend, fishing or staying at home?
We should prevent pollution ______ happily.
.It is sleeping late in the morning that ______ being late for work.
______ such heavy pollution already, it may now be too late to clean up the river.