______ he referred to in his article was unknown to the general reader.
__________ made her parents worried a lot.
The matter__________your study surely requires__________carefully.
__________in her best suit,the girl tried to make herself __________at the party.
__________ with the size of the whole earth,the highest mountain doesn’t seem high at all.
—You __________part in the party on time.—Sorry,I was delayed by the accident.