No one knew what because of the thick fog.

As we all know, apples are sold by ____ weight, and socks are sold by _______dozen.

Tom wants to know if you ___ a picnic next Sunday.—Yes. But if it ___， we’ll visit the museum instead.

After visiting different countries, I found _______ very important to learn about table manners.

Aprofessorandawriter_________presentatthemeeting.