. Marry notices are placed in the park warning people to ____ the grass.

While listening carefully,  the students＿＿＿ what their teacher said. 

It is required that each restaurant have signs on the walls,saying “ _____ your steps!”.

Some insects __________ the color of their surroundings to protect themselves.

Tom was late for school ___________________, which, of course, made his teacher very angry.