[求助]gwd-17-21

totolin116

Q21:

Medicare, the United States 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

偶想问问答案c中for 前面的逗号作何用？像这种 介词+which 的结构不是一般紧跟所修饰名词的吗？麻烦各位赐教~~~

gonghao

非限制性定从which引导，将pay for的介词前置

非限制性定从的结构紧跟先行词的

totolin116

那逗号去掉也可以吗~？