-- How long do you think it will be ______ the bus arrives here?
-- No more than five minutes.
A．when B．before C．since D．after
Making a proper choice ______ the future will probably make much difference in our life.
A．concerning B．to concern C．concerned D．having concerned
In Canada, cross country skiing is a popular sport among people ______ they can enjoy excitement and adventure.
A．that B．where C．whom D．which
According to what he complained about, something must have gone wrong with the computer, ______?
A．mustn’t it B．didn’t he C．hasn’t he D．didn’t it
an important position in a big company, Richard has a good chance to improve himself.
A．Offered B．Offering C．Having offered D．To offer
It worries the couple a lot ______ their only son is behaving worse and worse these days.
A．how B．why C．that D．what
