听力原文：Can you image ice that does not melt and is not wet？ Have you ever heard of dry i

听力原文： Can you image ice that does not melt and is not wet？ Have you ever heard of dry ice？ Dry ice is made by freezing a gas. It is quite different from ordinary ice which is simply frozen water. Dry ice was first manufactured in 1925. It has since fulfilled the hopes of its adventure. It can be used for making artificial fog in the movies. When steam is passed over dry ice, a very dense vapor rise. It can also be used for destroying insects in grain supplies. It is more practical than ordinary ice because it takes up less space and it's 142c colder. Since it turns into steam instead of melting into water, it is cleaner to use. For these masons, it is extremely popular, and many people prefer it to ordinary ice. Dry ice is so cold that ff you touch it with you bare fingers, it will burn you.

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A．Chemicals.

B．Water.

C．Gas.

D．Vapor.