Ki is my best friend.

The base of this building is very strong.

He continued to search to find the origin.

There are three pyramids in Egypt.

This plan was made based on facts.

The use of mobile phones is prohibited during class.

There is a class observation at my son's school tomorrow.

This reaction occurs through a chemical process.

He is an excellent chemist who made many discoveries.

He is an expert in petrochemistry.