No one ever complained before, you know.

I send the managing director a memo about your complaint.

Since there have been complaints about the quality of the water in the river, residents must be avoiding the river because they think that it is not clean enough.

When he realised it was a fake, and that none of the questions appeared on the actual exam, he complained to the police, who launched an investigation.

The company was finishing a major renovation to address complaints that its stores were messy.