Good technique in medicine means less pain and fewer deaths and, __________ it is our duty to masterit.
| A．altogether |
| B．therefore |
| C．otherwise |
| D．however |
—It’s hard to believe that Jack ________ have fought with the policeman.
—Yes. If one ________ ask for trouble, it can’t be helped.
| A．would; will | B．must; may | C．should; must | D．need; dare |
If our car had not ________, we would have been here on time.
| A．broken out | B．broken into | C．broken away | D．broken down |
This new kind of chemicals will help keep the air, soil and water________ from pollution.
| A．free | B．empty | C．loose | D．short |
Barack Obama has taken personal blame ________ the security failures which led ________ the attempt to blow up a plane on Christmas Day.
| A．of; to | B．for; to | C．on; on | D．in; on |
―Look! What a mistake! Why?
―Sorry, I _________ on it.
| A．don’t concentrate | B．hadn’t concentrated |
| C．haven’t been concentrating | D．wasn’t concentrating |