我在达拉斯待很长时间，但芝加哥仍然是我的基地。

I spend a lot of time in Dallas, but Chicago is still my ___base.

尼斯是探索法国里维埃拉的绝佳基地。

Nice is an excellent ___base for exploring the French Riviera.

它也有作为渔业基地的功能。

It also has a function as a ___base for the fishing industry.