_____ lie in the sun for too long, _______ you will get sunburnt.

Nuclear science should be developed to benefit the people _____ harm them.

When we think of communication , we _________ think of using words---- talking face to face, writing messages, and so on .

It is generally believed that a successful Olympic Games            relies on well-performed IT services.

Much to my surprise, the eight-year-old boy       fixed my computer within ten minutes．