Demography is an important tool for understanding various aspects of society.

His efforts were like a mantis trying to stop a chariot, he couldn't achieve any results.

Dou is a popular dancer.

He trampled on my heart.

He was peeling the apple skin.

He became lost in the crowd.

His heart seems to have frozen.

Please go straight down this road.

His answer was unexpected.

He answered my question immediately.