People should be cautious ______theirpersonal information when surfing the Internet so as to prevent certaincomputer viruses ______ it.

1Sun Tao has had a _______ English course, but he still doesn’t know

The ruler is _______ . Give it to _______, please.

— Do you think we should accept that offer?— Yes, we should, for we______ such bad luck up till now, and time _____ out. [ ]

oser the blood relationship between two people, the closer they are in intelligence. If we take two unrelated people _____, their degree of intelligence might be completely different.