There is a 20 minute parking _____ here, so we must get back to the car very quickly.

All the students are looking forward to the first _________ to pass the College Entrance Examination.

 It was ______ to go down the hills.

If we are all willing to make____with each other_____when we are in dispute，quarrels and conflicts will be avoided and we will surely live in peace.

As we know, too much ________ to Xrays can cause skin burns, cancer or other damage to the body.