_____the beginning of the 19th century did scientists know that all matter is made up of atoms.A,At B,By C,Up to D,Not until
I felt somewhat sad and was about to leave ____ something happened which drew My attention.
Everyone wants to have a holiday,but you have no idea____tiresome it is to rest.
.I won’t let you in____you show me the written permission of themanager.
.What you told me is really true,____?
Jack said Betty had always been interested in geography,____?