He is viewing that situation as a serious problem.

He views that situation as a problem.

No problem, I will do that job.

That proposal is completely unthinkable.

As a practical question, how are we going to fund this project?

In ancient Japan, the 方相 played an important role.

As the lunar phase changes, the night sky scenery also changes.

In Japanese grammar, the passive voice is used to create a passive form.

This phase diagram shows the state of the substance.

In this chemical reaction, the gaseous phase plays an important role.