The traffic light turned red, so I stopped.

His opinion is always rational.

Please check before you throw away the eggshell.

He is serving as the president's guard.

He drew a pentagon on the blackboard.

What is this mixture made of?

Metalinguistics is an important concept in linguistics.

In this project, it is necessary to combine various data.

It's difficult to remember new words.

His native language is Spanish.