The four of us haven't been out together for a while, have we?
Us four haven't done anything fun together for a long time, have we?
この場合、次のような言い方ができます。
ーThe four of us haven't been out together for a while, have we?
「4人でしばらく出かけてないよね」
to be out together で「一緒に出かける」
ーUs four haven't done anything fun together for a long time, have we?
「4人でしばらく何も楽しいことやってないよね」
to do something fun together で「一緒に何か楽しいことをする」
ご参考まで！
"最近この4人で遊んでないねー"
- The four of us haven't hung out in a while.
- Us four haven't been able to hang out for some time.
- We haven't been able to hang out recently.
最近みんな忙しいから4人で遊ぶことができないな。
- Since everyone is so busy, the four us haven't been able to hang out.
カナダ 
アメリカ合衆国 
