It is difficult to write rules that tell exactly when we should apologize, and it is not difficult to learn how to do it

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.

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

Women nowadays have more free to participate in social activities.

The guide told the tourists that it was a good restaurant specializing in seafood just round the corner from the museum.

We had better to review this lesson carefully because we will have some questions on it.