---Would you please repeat the grammar rules again? ---Of course, but I am sure that you _______ to me carefully, as I have told you twice already.
This machine _______. It hasn’t worked for years.
I would rather _____ a little earlier to avoid ________in the rush hour traffic.
He speaks English well indeed, but of course not ______ a native speaker.
It was ____ that he had to ask for help.
Pierre Curie stopped his research and _______ Marie in the search of an unknown material.