巴豆,如果大剂量地服用,则会导致严重腹泻;如果服用适量,则能治好慢性腹泻。由“泻药”到“治泻药”的变化说明( )
The professor along with his assistant came in, ________ by a group of excited students.
Nobody noticed the thief enter the house because the lights happened to _______.
The headmaster suggested that a good preparation ________ ahead of time.
--- What is that wonderful smell? --- Our neighbor ________ for a party.
He hardly reads English out aloud at home, ________?