Another way of doing it is highlight the text using the mouse,Then right click & select copy.Then when you are ready you right click again & choose paste.
I have just put the mouse line beside the 'h' of the word 'how' of your question. If you then left click 3 x you will highlight that sentence.
Go to edit and select 'copy' ( or ctrl + C, or right click ) and then paste.
If you try any other method to copy something in AB you will end up with a mass of unwanted stuff.
Hope this helps.