How is your grandparents ? —-They are __________.

Another drug that has helped improve people’s health is penicillin, _________ is _________ by many _________ one of the most important medicines.

_____weekdays, I usually go to school_____about 7 :30.[ ]

You must be careful when you go ______ the street. [ ]

Two ______ trees have been planted along the lake since 1998.