After he was knocked down by a bike, he was badly hurt and had to ______ to his feet. 

I’m putting on weight. The doctor has warned me to      sugar.

---Oh, doctor, the wound on my leg is infected.---You really shouldn’t have left it _______ to the sun.

Recent studies have shown that most US graduates receive cash as gifts, though the amount received ______ from person to person．

According to school bus safety rules, when a school bus stops on the road to _____or pick up students, other vehicles behind it must stop to wait.