Lastnighthesawtwodark_____enterthebuilding,andthentherewastheexplosion.

Humanbeingsaresuperiortoanimals_____theycanuselanguageasatooltocommunicate.

The aeroplane ____ she was traveling was delayed for three hours at least.

I still remember the days ____ we studied together.

Thelandladywasverystrict.Sheaskedthatwe____televisiononweeknights.