What does the sign over there read—“No person __________ smoke or carry a lighted cigarette，cigar or pipe in this area.”

―_____ Jim and Sam your classmates ―No, _____ are in different classes.

You dare not go alone, you?

Many people are __________ building a chemical factory（化工厂）near here . They are worrying about the possible pollution .

They are discussing what to do for the disabled.— ___________is necessary to provide them with more positions.