When the expression first came into being, people refused to use it but _____ they began to accept it.
| A．usually | B．gradually |
| C．frequently | D．quickly |
I didn’t mean to break your vase—it was just ______.
| A．an accident | B．an advantage | C．an agreement | D．an experience |
He was breathing ______ after the relay race.
| A．heavily | B．slowly | C．carefully | D．weakly |
People are concerned about the quality of the air they ______.
| A．hear | B．eat | C．drink | D．breathe |
She walked home by herself, ______ she knew that it was dangerous.
| A．if | B．so that | C．although | D．because |
—Let's go Dutch for this supper, OK?
—No，________this time, as a reward for all your help.
| A．it's up to you | B．it's my treat |
| C．let's talk about it | D．it doesn't matter |