It is difficult to find the optimal solution to this problem.

The manufacturing industry occupies an important part of the economy.

We are considering introducing a new production line.

He studied for at most one hour.

He is very tall.

Highways are convenient for commuting.

This building boasts the maximum height in this town.

This bridge is reinforced with steel wire.

He picked up the steel ball and stared at it intently.

This building is strengthened by using silicon steel.