Jack wasn't saying anything，but the teacher smiled at him ________ he had done something very clever.(2011·湖南)
A．as if B．in case C．while D．thought
—Did you return Fred's call?
—I didn't need to ________ I'll see him tomorrow.
A．though B．unless C．when D．because
Leave your key with your neighbor ________ you lock yourself out one day.(2012·辽宁)
A．as long as B．even though
C．in case D．as if
A number of high buildings have arisen ________ there was nothing a year ago but ruins.(2012·山东)
A．when B．where C．before D．until
—Do you have a minute？I've got something to tell you.
—OK，________ you make it short.
A．now that B．if only
C．so long as D．every time
—Have you got any idea for the summer vacation?
—I don't mind where we go ________ there's sun，sea and beach.
A．as if B．as long as
C．now that D．in order that
