单选题 In the next 40 years, the number of people in the United Stated over the age of 65 1 expected to double. 2 the needs of this part of the population is a 3 . To a large 4 a society is 5 by how it cares for those who can no longer care 6 themselves.
High technology shows the most 7 advances in helping the elderly. 8 the well-known artificial (人造的) heart implantation (移植), there are great achievements in 9 artificial lungs, livers, and bones. An electric ear is already seventy-five percent effective. They will serve better medical care.
For the 10 people, even the simplest tasks can be difficult, sometimes 11 to perform. American businesses have satisfied 12 with different kinds of 13 but useful products. Companies have designed extra-efficient can openers that enable people 14 hands have become too weak 15 cans easily. There are devices that 16 people to pull on a pair of socks 17 straining (扭伤) their backs. Combs 18 long handles and unshaped back brushes are 19 for those who can not reach as far as they could 20 they were young.