用所给单词的适当形式填空(10分)
小题1:Mary ______ to do her homework. (have)
小题2:Monday is cold but Tuesday is _____ (cold) than Monday.
小题3:We have P.E. classes _________ (one) a week.
小题4:If you want to keep _____( health ), you'd better take more exercise and eat less food.
小题5:They _________(not have) any classes next week.