Improved the grammar in README (agronholm#444)

README.rst

@@ -12,12 +12,12 @@
  :alt: Gitter chat
 
 AnyIO is an asynchronous networking and concurrency library that works on top of either asyncio_ or
-trio_. It implements trio-like `structured concurrency`_ (SC) on top of asyncio, and works in harmony
+trio_. It implements trio-like `structured concurrency`_ (SC) on top of asyncio and works in harmony
 with the native SC of trio itself.
 
 Applications and libraries written against AnyIO's API will run unmodified on either asyncio_ or
 trio_. AnyIO can also be adopted into a library or application incrementally – bit by bit, no full
-refactoring necessary. It will blend in with native libraries of your chosen backend.
+refactoring necessary. It will blend in with the native libraries of your chosen backend.
 
 Documentation
 -------------
@@ -30,7 +30,7 @@ Features
 AnyIO offers the following functionality:
 
 * Task groups (nurseries_ in trio terminology)
-* High level networking (TCP, UDP and UNIX sockets)
+* High-level networking (TCP, UDP and UNIX sockets)
 
  * `Happy eyeballs`_ algorithm for TCP connections (more robust than that of asyncio on Python
  3.8)