_____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
Tom was very angry about ________ to Mary’s birthday party.
Energy drinks are not allowed _______ in Australia but are brought in from New Zealand.
The disaster is so serious that the people in that area really have a lot of difficulty ______ with their lives.
Having a walk after supper is certainly good for the old people, but it remains ______ whether they will enjoy it.
If better use is _______ your spare time, you will have a more brilliant future.