live in a family groups 为什么要group要加s

live in a family groups 为什么要group要加s We often work in groups in calss.为什么group要加s? live as a family 等于 live in family groups 吗? let's talk about the picture in groups.groups为什么要加S,pair呢 英语翻译Wolves live in groups called "packs".They have a family mr happy live in flat 8a中的live要加s么 work with a group和work in groups的区别 It's a wonderful place to live.为什么不在live后加in wolves live in family groups if they are in danger对 in famil pandas live in China.live为什么不加s? in january还是on?还有My family usually clean(clean要不要加s,为什么)the group of+（数字）中group要加s吗?