complain|complained|complains|complaining

他去看医生，因为他一直在诉说胃痛。

He went to the doctor because he had been ___complaining of a stomach ache.

很多人投诉了噪音问题。

Lots of people have ___complained about the noise.

他总是在抱怨！

He's always ___complaining!

如果服务这么差，你为什么没有向经理投诉呢？

If the service was so bad, why didn't you ___complain to the manager?

她经常抱怨食堂饭菜的质量。

She often ___complains about the quality of the food in the cafeteria.