(2010·福建)The girl had hardly rung the bell ________ the door was opened suddenly，and her friend rushed out to greet her.
A．before B．until C．as D．since
(2010·新课标全国)Mary made coffee ________ her guests were finishing their meal.
A．so that B．although C．while D．as if
(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
