Q21:

Medicare, the LACE w:st="on">United StatesLACE> government’s health insurance program for the elderly and disabled, covers the full cost of home health care, but not with other nonhospital services where 20 percent of the costs must be paid by beneficiaries.

1. but not with other nonhospital services where 20 percent of the costs must be paid by beneficiaries
2. but not of other nonhospital services, making beneficiaries pay 20 percent of the costs
3. but not of other nonhospital services, for which beneficiaries must pay 20 percent of the costs
4. which is unlike other nonhospital services in that 20 percent of the costs must be paid by beneficiaries
5. which is unlike other nonhospital services that make beneficiaries pay 20 percent of the costs

key:C

我选B

doing sth 作为伴随结果。C中which指代我觉得有问题。请教！