用所给词的适当形式填空。
My mother shops ____________ (two) a week .
We had an ______________(enjoy) trip last week.
The best way ______________(exercise) is to run every day.
She usually sleeps ___________ (little) than eight hours at night.
I think English is the ___________(easy) of all our subjects .
Tina is ______________(friendly) than Betty .
Alice is not as __________(quiet) as her sister .
We should take study ____________(serious).
We must study hard to make a big ________________(different).
I stayed at home ____________(many) of the time to read.