Dear Babystudent, Diana,
 
 �Thus � (a formal or literary adverb)
 1) �Thus � =  �As a result or as a consequence of this �.
"Angela Mirkel won the election, thus becoming President".  (That is how she became President).
 
2) �Thus � =  �In this way �;  �In the manner now being shown or indicated �.
"Hold the pen in your hand, thus, the way that I am holding my pen". (Teacher shows the student the pen in the hand.)
 
3)  �Thus � = A modifier,  �Up to this time �;  �Up to this point �.
"England are winning the football match thus far!" (Up till now, England are winning but it may change!")
 
1)  �Hence � =  �As a consequence �;  �For this reason �.
"There are thousands of lorries, hence a lot of pollution"  (That is why there is pollution.)
 
2)  �Hence � = When used after a period of time,  �From now �.
"In two years hence, because of improved trade, my country will probably be rich".  (In two years � time ... ...).
 
3) Hence =  �From here � (very old-fashioned, archaic, not now used.)
"Leave my house.  Get hence!"  (Get out of here!)
 
 �Therefore � =  �For that reason �;  �consequently �.
"The dancer broke her leg, therefore she couldn �t enter the Dance Competition.  (That is why she couldn �t... ...).
 
The words  �thus �, and particularly  �hence �, are literary, formal words, not often used by  �ordinary people � in the area where I live, except in documents and in University work.
 
I hope that this helps you.
 
Bis Spater!  Tschuss!
 
Les