How to use Wikipedia's API for making auto response chatting software?

[sazzad hossain rafi]

I want to make a software which will give reply if I want to know about a certain thing.Like,if I said the app "United States " then it will give me information of "United States" from wikipedia which is  exactly found in 

link:  https://en.wikipedia.org/wiki/United_States  

I want to get the first paragraph of a Wikipedia article.

I have seen a app (link: https://sites.google.com/site/appinventor/amazon-at-the-bookstore   ) 

[Taifun]

Note that we don't provide general App Inventor support here, but general help is available at the MIT App Inventor Forum.
You might want to follow your thread there https://groups.google.com/d/msg/mitappinventortest/BtvvemH6mAM/KRDH8rycCgAJ

Taifun