Does doing harm to another harm the wrong doer as well

What is the meaning of the word checking as it is used in this sentence from the second paragraph of the passage?

The vertical height of a soccer ball can be represented by the following function, where h(x) represents the height, in feet, x seconds after the soccer ball is kicked. rewrite the function in the form that reveals the times at which the soccer ball is on the ground.

When the telephone rings incessantly, what is it that the men want to have happen? they want the phone to be answered because it is jangling their nerves. they want mr. frank to go to the office and answer it because they are afraid it might be bad news. they want mr. frank to go to the office because they think it might be miep. they want mr frank to ignore the phone.