He is known as a person with learning.

This audio is very clear.

The sound was so quiet that I could hardly hear it.

He is an expert in orthoepy, teaching pronunciation.

The sound effects of this movie are amazing.

Phonons are an important concept in solid state physics.

It is important to understand the importance of health.

Draw a straight line.

This laser ray is very powerful.

We are focusing on the research and development of new products.