He visited the used bookstore to resell old books.

My biorhythm is disturbed, and I've been tired lately.

He has three photos.

We study every day to cultivate new skills.

I cleaned the window that was dirty with soot.

Bioinformatics is an essential field for the analysis of biological data.

She bought a new vibrator.

He joined the multi-level marketing business.

He decided to start a multi-level marketing business.

This consumer boycott is a response to the inappropriate actions of the company.