单项选择题
In his lecture Prof Smith has （）a wide range of subjects.
A.coveredB.expressedC.releasedD.revealed
单项选择题 （）the lake around our university was seriously polluted.
未知题型 People haven‘t realized the seriousness which this earthquake has caused.
单项选择题 He departed （）to catch the train onlyto find his ticket was left in home.
