He prefers natural foods.

Calculating the natural logarithm is an important part of mathematics.

His car spontaneously combusted all of a sudden.

This wood may spontaneously combust if the humidity is high.

Natural rights are rights that humans have from birth.

We must strive to protect the natural environment.

We have a responsibility to protect the biodiversity of the Earth.

The Cultural Revolution is a part of China's history.

Natural language understanding is an important field of artificial intelligence.

We are planning to visit the nature reserve this weekend.