شرکت در آزمون آنلاین زبان انگلیسی 1 - زبان انگلیسی 1 | آزمون شماره 13411

The Great Wall of China was originally built … . 

Vitamin D is important for health and growth. It is used by the body to form strong bones and teeth. That is why growing children need it.

Vitamin D is called “the sunshine vitamin”. It is formed when you are in the sun with no clothes. Long before people knew what vitamin D was, they found out that sunshine was important.

Poor children who lived in crowded places were often ill. In England a tax (money you pay to the government for its services) was once placed on windows. Buildings put few windows in houses. The lack of vitamin D became so common that it was called “the English disease”.

Vitamin D is called “the sunshine vitamin” because it … .