Use "The" Precisely

The definite article is used to indicate the specific noun or nouns that we talk about like The Himalya, The Ganga etc etc..
Reason: The is the article which is used to indicate a noun which is unique or specific. From above examples you can guess correctly. Ganga is a river and is unique. There is no other river named Ganga. So it is The Ganga.

Important: This definite article does not applies to generalized noun or a noun that indicates group. For e.g.

France is a beautiful country
Red skirts are very sexy
Children are very creative

So if you have a difficulty to determine whether to apply "The" or not, try to determine if noun used is a specifc or a general. If its general, do not use "The". Simple, isn't it??
These small small things makes up grammar as a whole. Many times you can eliminate options in the summary/CR type of question just by checking such small errors. The bottom line is, get your eyes used to with such errors. You should not take even a fraction of a second to identify such errors. These basic things lays a foundation of you grammar prowess.

Ameya