Copy edit ConditionVariable.md

Make minor copy edits.

Author: Amanda Butler

docs/reference/api/rtos/ConditionVariable.md

@@ -1,14 +1,14 @@
 ## ConditionVariable
 
-The ConditionVariable class provides a mechanism to safely wait for or signal state changes. A common scenario when writing multi threaded code is to protect shared resources with a mutex and then release that mutex to wait for a change of that data. If this is not carefully done this can lead to race condition in the code. A condition variable provides a safe solution to this problem by handling the wait for a state change along with releasing and acquiring the mutex automatically during this waiting period.
+The ConditionVariable class provides a mechanism to safely wait for or signal state changes. A common scenario when writing multithreaded code is to protect shared resources with a mutex and then release that mutex to wait for a change of that data. If you do not do this carefully, this can lead to a race condition in the code. A condition variable provides a safe solution to this problem by handling the wait for a state change, along with releasing and acquiring the mutex automatically during this waiting period.
 
 ### ConditionVariable class reference
 
 Coming soon
 
 ### ConditionVariable example
 
-Below is an example of ConditionVariable usage, where one thread is generating events every 1s, and the second thread is waiting for the events and executing some action.
+Below is an example of ConditionVariable usage, where one thread is generating events every 1s, and the second thread is waiting for the events and executing an action.
 
 ```
 #include "mbed.h"