27.After his wife died, he kept himself _____ from other people and the outside world,
We _________ the difficulty together, but why didn’t you tell me?
________ at the door before you enter my room, please.
________ with care, one tin will last for six weeks.
— Can I have a day off tomorrow, Mr. Johnson? — ________. I can manage without you.
—Why not have a birthday party for our mother? —________.