This exam is very difficult. Many students are concerned the results.
John may phone tonight,I don't want to go out ______ he phones.
He is always helping people without expecting anything ______.
I will mark ______ everything you say.It is helpful to the English learners.
—Believe me,all your efforts will ______ some day. —Thanks for your encouragement.
Some blood types are quite common,others are regionally______,and still others are rare everywhere.