Octacosane is a compound often used in organic chemistry.

I have visited Shanhai Pass.

Liquid oxygen is often used as rocket fuel.

Computational geometry is an important field of computer science.

He is working on his job with intense concentration.

He is an expert in electronic phototypesetting.

He is creating a newspaper using an electronic phototypesetter.

Santa Claus delivers presents to children.

He drew a triangle on the blackboard.

I am planning to go to San Francisco next week.