—Where on earth have they gone?—I have no idea, but I wish I .
Mr. Black must be worried about something. You can________it from the look on his face.
When the lawyer asks you questions about the case, you should be________.
—How many days are there in February? —________thirty days.
Tom is________a common worker. How disappointed his parents are to see he hasn't gained great achievements!
A writer cannot write good works without practice________more than a director can direct excellent plays without experience.