The passage below contains 10 mistakes. Identify and correct the mistakes. Write youin the box provided

The passage below contains 10 mistakes. Identify and correct the mistakes. Write you
in the box provided. 
 All languages change over a period of time, for reasons which are imperfectly 
understood. Speech is really such integral a form of human activity that it cannot be 
regarded as an entity in itself. With this reason, it is more exact to say that each 
generation behaves linguistically in a slight different manner from its predecessors. 
Young people are impatient of how they often consider to be the stilted vocabulary and 
pronunciation of his elders, and like to show how up-to-date they are by using the latest 
slang. Moreover, as the years go by, some of that slang becomes standard usage. In 
any case, people slowly grow far less receptive to linguistic novelties, so that by the time 
they reach their forty, they decry the slovenly speech of the younger generation. 
In this respect, language is a little alike fashions in dress. The informal clothes of one 
generation become the everyday wear of the next. Similarly, just as much young doctors 
and office workers carry out their duties in casual clothes, so expressions which were 
once confining to slang and familiar conversation are assimilated into their normal 
vocabulary.