After her son died in a car accident, the old lady would sit at the window, ______ out and _______ in thought.

______ Millie ______ Billy is patient with children. I think they can make excellent teachers.

Mary fell over and broke her leg.________，she will have to be away from school for about one month.

Could you drive me to the supermarket after supper if_________________

下列各句中，没有语病、句意明确的一项是（ ）