Before you ask someone for help, find out _________ he is the right person for your problem.
A.since B.whether C.unless
—It’s a pity that _________ my teachers _________ parents allow me to swim alone.
—After all you are too young, safety first.
A.either; or B.neither; nor C.both; and
—Lucy, you can’t use the phone __________ we are far from the gas（天然气）station.
—Ok, I won’t do that again.
A.when B.though C.until
—A little bird entered through the open window to join us for dinner last night.
—Wow, that’s interesting! The unexpected guest ________ be welcomed.
A.will B.can C.must
—More and more people prefer to walk rather than ride in cars.
—______________. Walking is good for health.
A.So they are B.So are they C.So they do
—What great progress Huawei _________ in recent years!
—No wonder it is widely known in all parts of the world.
A.is making B.has made C.made
