Eye doctors suggest that a child’s first eye exam____at the age of six months old.

Many Chinese students think sciencesubjects are _______ foreign languages.

How are your business goes wrong—But I have done all that is by law.

Whydoyou hang that photograph above thefireplace— ______ visitors of the memorial days of Long March，Sir.

If you sleep less than seven hours, you are three times moreto catch a cold．