A survey of the opinions of experts ________ that three hours of outdoor exercise a week ________

good for one's health. [ ]

A. show; are  

B. shows; is

C. show; is  

D. shows; are

GPON支持Triple－play业务，可提供全业务竞争方案可以有效解决双绞线接入的带宽瓶颈，满足用户对高带宽业务的需求，如高清电视、实况转播等，GPON是三网合一的上佳方案。