What’s the problem with paper napkins and plastic food wrapsA．They can’ t be recycled though they help people save time on housework.B．They become trash and therefore are harmful to the environment.C．They add cost to the product and thus make it more expensive.D．Sometimes they are not strong enough to hold the purchase.

单项选择题

Questions 17-20 are based on the following passage. You now have 20 seconds to read questions 17-20.

What’s the problem with paper napkins and plastic food wraps

A．They can’ t be recycled though they help people save time on housework.
B．They become trash and therefore are harmful to the environment.
C．They add cost to the product and thus make it more expensive.
D．Sometimes they are not strong enough to hold the purchase.