Could you bring me that, whatchamacallit?

The calculus of variations is a branch of mathematics that deals with the optimization of functions.

He wrote a poem using the four treasures of the study.

You can use spectroscopy to examine the components of a substance.

I prefer tea over coffee.

I am taking a class in Literary Chinese.

We visited the annex of the art museum.

He is rumored to be engaged in intelligence activities.

This app is really convenient.

Without his help, we wouldn't have been able to complete this project. That's why we prize his presence.