“In the desert, oases are few and far between.”　「砂漠ではオアシスが少ない。」

“You’ll probably have to take your trash home with you. Trash cans here are few and far between.”　「ゴミは持って帰ることになるでしょう。ここにゴミ箱は少ないです。」

何かの数が少ないならfewと言います。一か所に集まっていないなら、お互いに距離がある。これでは見つけるのが大変です。

When there are not many of something, there are few. If they are not all clustered together, there is a long distance between them. This makes them hard to find.