Update 01-chapter3.markdown
Update 01-chapter1.markdown

The sentence did not make sense, so I hopefully could write it in a more clear format.
Merge pull request #781 from FrankLo/patch-1

Update 01-chapter1.markdown
Merge pull request #780 from wakeup/master

Update 01-chapter3.markdown
[bg] Merge branch 'master' into bulgarian