He was my travel companion.

Ruminants have the characteristic of re-chewing food after swallowing it once.

His insight greatly contributed to the success of the business.

My pet is a dog.

This main road is convenient for commuting.

He is an expert in dynamics.

He is an expert in dynamics, helping to solve complex problems in physics.

Understanding the principle of electromagnetic induction is very important in learning physics.

My father drives a truck.

The fire truck went into action because of the fire.