There can be various ways of constructing statements to compare two or more people or things.

* In an affirmative statement we use as+ adjective(positive form)+ as. In a negative statement we use not as/not so+ adjective(positive form)+ as.

eg. She is as tall as her mother.

       He is not as intelligent as his sister.

* With the comparative form of adjective, we use than

eg. My dress is prettier than yours.

       This plot is more expensive than I thought.

At times than is omitted

eg. I didn’t think this plot would be so expensive.

* In statements where three or more people/things are compared, the+superlative form of adjective is used.

eg. This is the best school in town.

       It is the worst movie I’ve ever seen.

* Gradual decrease or increase is expressed in the form comparative + and+ comparative.

eg. The weather is becoming hotter and hotter.

       Gradually you are getting slimmer and slimmer.

* Comparisons can also be made using like and as

eg. He runs like a leopard.

       Work hard as your mother does.

One should be careful in using the two words like and as. They may change the meaning of a statement.

eg. Sam worked like a slave in his company. (worked really hard)

Sam worked as a slave. (he was a slave)