There was a hole in the door, through which I 　　　 sight of Mr. Brown sitting in a chair. 

Though the "No smoking" signs have existed for long in public places, heavy smokers often  them and light up cigarettes.

The government will __________ the country through the difficulties ahead.

One of the greatest benefits of stamp－collecting is that they are based on common interests，________ appearance，age or wealth.

. One day I ____________a newspaper article about one in six European mammal species threatened with extinction.