On Saturdays, students are very proud to be         on the street to guide passers-by to obey traffic rules.

The man has gained an evil reputation. That’s to say he has a bad _____.

There might be life on other planets, but so far scientists haven’t found enough _____ to prove it.

Sometimes, the _____ of humor in this country causes misunderstanding in other countries.

In America, turkey is served as the main course on special ________.