A:Since
B:A
C:For
D:Because of
Suggested questions:
①How many class rules do you have?
②What must you do in the class?
③What mustn't you do in the class?
下列几种能量来自于太阳的是( )
把过量的CO2气体通入下列物质的饱和溶液中,不变浑浊的是 ( )