.I tried to call on you last week but your dog simply ____ not let me come through the gate.

— Why do we get up so early?— If we ______ the flight we would have to stay here for another day. 

There was a lot of fun at yesterday’s party. You______come, but why didn’t you?

If it _________ not for all the cars and passers-by with cameras, you _________ think you have magically traveled back to the 14 century.

Messages ______ be changed from sound into electricity before they ______ be sent by radio.