我在网上查了航班的可用性，有很多选择。

I checked the ___availability of flights online and there's plenty of choice.

因此，在预订行程时，必须考虑我的可用性。

Therefore, it is essential that you take account of my ___availability when booking the trip.

新鲜农产品的可用性随季节变化。

The ___availability of fresh produce varies by season.