Perhaps you should try some spelling variations:
vpython collisions » vpython colisoes (Expand search), proton collisions (Expand search), photon collisions (Expand search)
decrease tutoring » decrease during (Expand search), decrease suffering (Expand search), decreased during (Expand search)
tutoring program » mentoring program (Expand search), monitoring program (Expand search), training program (Expand search)
collisions on » collisions in (Expand search), collisions of (Expand search), collisions and (Expand search)
decrease at » decrease akt (Expand search), decrease and (Expand search), decrease in (Expand search)
at decrease » rate decrease (Expand search), that decrease (Expand search), and decrease (Expand search)
on python » in python (Expand search), of python (Expand search), _ python (Expand search)

You may be able to get more results by adjusting your search query.

• Removing quotes may allow a broader search: (( decrease at decrease tutoring program ) OR ( vpython collisions on python programming ))~.