By the turn of the century, most of the inventions that were to bring in all the comforts of modern living has already been thought of.

These snakes will not cause you any serious harm. They are harmful.

A beaver uses its strong front_teeth to cut down trees and peel_off its bark.

The clerks who are happy to wait for their customer will get promoted soon.

The eastern bluebird is considered the most attractive bird native of North America by many bird-watchers.

Not one in one hundred children exposed to the disease are likely to develop symptoms of it.

Parks which are found in downtown areas where office workers and store employees can enjoy their lunch hours sitting on the green grass in clean, fresh air.

Mercury and alcohol are widely used in thermometers because their volume increases uniform with temperature.