They were too close to the door to close it.

The word 'close' is used twice with different
meanings.

1 - say clouz  It means to be near, by or at.

2 - say clouz.  It means to shut.

Another way to say this is:

The door could not be shut because they were in it's
way.

or 

They needed to step back to give the door room to
swing shut.

06/27/2002