Exercise for the Breakout

Write a program which allows the user to build up a sentence one word at a time, stopping when they enter a period (.), exclamation (!), or question mark (?)

example interaction:

In [1]:
%run b1sol.py
Please enter a word in the sentence (enter . ! or ? to end.): My
...currently: My 
Please enter a word in the sentence (enter . ! or ? to end.): name
...currently: My name 
Please enter a word in the sentence (enter . ! or ? to end.): is
...currently: My name is 
Please enter a word in the sentence (enter . ! or ? to end.): Slim
...currently: My name is Slim 
Please enter a word in the sentence (enter . ! or ? to end.): Shady
...currently: My name is Slim Shady 
Please enter a word in the sentence (enter . ! or ? to end.): !
--->My name is Slim Shady!
In [ ]: