The Internet is increasingly accessible at school and at home. _____many parents and teachers are sometimes not as prepared as we should be to warn children about Internet threats.

 Just as a book is often judged ______ by the quality and appearance of its cover, a person is judged immediately by his appearance.

At first the institute refused to purchase(购买)  the  experiment  instrument,  but  this decision was ______ changed.

Make sure the gas is turned off after a bath, which would ________ cause danger.

He was breathing ______ after the relay race.