A terrible thought Mr. Smith when he was leaving for work: what if an accident happened while his son was alone at home?
| A．insured | B．freed |
| C．attacked | D．struck |
Delta, the American airline, is sometimes jokingly explained “Don’t expect your luggage to arrive” because it ______ be very slow.
| A．should | B．must | C．can | D．will |
Life is more than merely trying to achieve thestandards of society but trying to be a good person ______ one’s own standards.
| A．at | B．in | C．on | D．by |
______ herself in looking after the newly-born twins, she had to sacrifice her career to stay with her kids.
| A．Occupied | B．Being occupied |
| C．Having been occupied | D．Occupying |
--- What is your strongest memory of the bombing attack?
--- If I ______ rightly, we were about to approach the finish line when a big bang struck my ears.
| A．will remember | B．had remembered | C．remember | D．remembered |
More and more people have come to realize that if we had taken effective measures much earlier, the air quality ______ so seriously now.
| A．is not polluted | B．would not be polluted |
| C．had not been polluted | D．would not have been polluted |