ail|ailing|ails

最近是什么事情让你如此困扰？

What has been ___ailing you so much lately?

她的膝盖疼痛一直困扰着她。

The pain in her knee ___ails her constantly.

这些植物因为缺乏阳光而生长不良。

The plants are ___ailing due to lack of sunlight.