One fifth of the earth's surface is covered by permafrost.

The subway is faster than the streetcar.

In the underground, to double-cross any member means sure death.

The position is conditional on how well you are able to perform.

No one equals him in intelligence.

It is important to have intellectual curiosity.

I enjoy intellectual conversations.

Knowledge has been passed down to subsequent generation.

Zeal without knowledge is a runaway horse.

Who cares?