The pollution in this area has become a serious problem.

My white shirt got dirty with coffee.

It's sad to see his pure heart being defiled by lies.

We often have picnics by the river on weekends.

Please draw a blue line.

He told a lewd joke and made everyone laugh.

He likes to talk about lewdness.

Katsusuke is my best friend.

He is working as my helper.

I like his new song.