He solved complex mathematical problems using his new calculator.

My new vacuum cleaner is very quiet.

I can't afford to miss this opportunity.

The transmission of this car is very smooth.

My new computer is very fast.

He is fulfilling his responsibility as a president who controls state affairs.

My father is an aircraft pilot.

He works as a fighter jet pilot.

In psychology, it is important to understand the mechanism behind human behavior.

This engine is old, but it still works.