The photoelectric effect is a phenomenon where a material emits electrons after absorbing light.

We need to evaluate the cost-effectiveness of this project.

We need to evaluate the cost-effectiveness of this project.

Reducing greenhouse gas emissions is important for environmental protection.

He is an expert in ornithology, studying types of birds all over the world.

He is an expert in speleology and is exploring caves around the world.

He is majoring in meteorology at university.

He is passionate about his research in futurology.

He is majoring in analysis at university.

Let's eat lunch in the school cafeteria.