Add these sentences with correct variant according to the text. Using as a plan speak briefly about Water Supply

1. An adequate supply of pure wholesome and palatable water...

a)...is especially true of towns situated on large inland lakes or rivers, b)...is essential for the maintenance of high standards of health, c)...may be taken from any source of water, d)...should be protected from contamination by filtration.

2. There are cities whose geographical location...

a)...makes water pass through a very interesting cycle of treatment, b)...requires elaborate systems of water supply.

c)...makes the problem of water supply very difficult.

d)...calls for modern systems of water treatment.

3. The earliest settlers took advantage of natural water sources by...

a)...building water power stations on them, b)...establishing their colonies near them, c)...providing sufficient water supply for their needs, d)...using water without much preliminary treatment.

4. Due to man's vast activities at the present time... a)...various systems and methods of water treatment are required, b)...water must be obtained in unlimited quantities, c)...many inland lakes cannot be used as sources of water supply, d)...splendid sources of water supply are drilled wells.

6. Fill this table due to points of the topic Sanitary engineering