difficult前用什么介词（difficulty什么时候用复数形式）

前用介词in，例如：

1.We're living in difficult times我们正处在困难时期。

2.Happiness is the instantaneous fireworks, or helps one another in difficult time?幸福是瞬间烟火，还是相濡以沫？

3.At home, Jake watched a lot of TV programmes about living in difficult situations.杰克在家里收看了很多关于如何在困难处境中生存下来的电视节目。

 difficult前面可用介词of