【2012黔东南州】We can't pass the exam, ___________we study hard.
A. because B. and C, unless D. or
【2012 贵州六盘水】The man was so tired，___ he still went on working.
| A．so | B．but | C．or | D．and |
【2012 南宁】Mike was ill yesterday, _________ he didn’t go to school.
| A．if | B．but | C．so | D．or |
【2012广西柳州】Wang Dong didn`t go to school yesterday ________ he was ill.
A. so B. if C. because
【2012 佛山】Thewaterhereispolluted eventheanimalscan’tdrinkit
A. so B. because C. though