-----Do you know where David is ? I couldn’t find him anywhere.-----Well. He _______have gone far-----his coat’s still here.
Milk will turn sour soon on hot days ______ it is stored in the refrigerator.
You'd better not ride the bicycle on snowy days; you ______ fall.
—Hi, Jack.You look a bit fat now. —Yes, I ______ five pounds recently.
Every book ______ from the library should be returned on time.
My sister has a habit of keeping a diary and writes down ______ happens every day.