21. Which number should you call if you want to see an opera?

A. 241-2742. B. 723-1182. C. 381-3300. D. 232-6220.

22. When can you go to a concert by Chamber Orchestra?

　A. February. B. May. C. August. D. November.

23.Where can students go for free performances with their I.D. cards?

　A. Music Hall. B. Memorial Hall.

　C. Patricia Cobbett Theater. D. Riverbend Music Theater.

24. How is Riverbend Music Theater different from the other places?

　A. It has seats in the open air.

　B. It gives shows all year round.

　C. It offers membership discounts.

　D. It presents famous musical works.

B

History tells us that footwear was one of the first things ancient people learned to make. Footwear helped them across rocky paths or hot sands without injuring themselves. The earliest footwear we know of was simply a piece of plaited (编织的) grass or leather tied to the feet.

The ancient Egyptians seem to have invented the first footwear with a firm sole (鞋底) - sandals. Egyptian royalty usually wore sandals that had a different style from those with lesser status (身份), while slaves were not allowed to wear anything on their feet. The sandal is still the basic form of footwear in many countries, particularly those with a hot climate, whereas（然而） in cold climates, an entirely