(2011·四川)As is reported，it is 100 years ________ Qinghua University was founded.
A．when B．before C．after D．since
I'm sorry you've been waiting so long，but it'll still be some time ________ Brian gets back.(2008·北京)
A．before B．since C．till D．after
He had no sooner finished his speech________ the students started cheering.(2011·辽宁)
A．since B．as
C．when D．than
He smiled politely ________ Mary apologized for her drunken friends.(2012·山东)
A．as B．if C．unless D．though
(2013·重庆，25)________ we have enough evidence，we can't win the case.
A．Once B．As long as C．Unless D．Since
(2013·四川，7)He is so busy.He cannot afford enough time with his son________he wants to.
A．even if B．as if C．because D．before
