We are a team so we must assist one another _____ completing the task．
A．with B．to C．at D．in
—Excuse me, Madam．Taking photos is forbidden here out of security．
—I'm really sorry, I _______ of that．
A．am not informed B．hasn't been informed
C．hadn't been informed D．wasn't informed
The civil war broke out in Libya, ______ to the instability of the international oil price．
A．to contribute B．contributed
C．having contributed D．contributing
Recently a new social issue has been brought to everyone's attention ___ __food additives are abused．
A．when B．whether C．that D．which
While the police have already done a lot of investigation, much evidence ___ __.
A．is remaining to be confirmed B．remained to be confirmed
C．is remained to be confirmed D．remains to be confirmed
_____ on everyday practice, progress in English is a goal which can be achieved．
A．Based B．Basing C．Having based D．Being based
