Unless ___ to speak,you should remain silent at the conference.
Mr. Green drove slowly on the way home until he reached the high way, ______ the speed limit was 60 miles per hour.
Life is like a tale. ________ matters is not how long it is, but how good it is.
—Tom went to Beijing for a holiday yesterday. —________.We played football together this morning.
The house is dirty because it ________ since they moved out.
—Is the letter from your mother? —Yes.But she ________the letter herself,because she doesn’t even know one word.