A:C2H4
B:C3H8
C:C4H8
D:C5H10
— You can't imagine ______ little ants can carry ______ heavy a thing.
— That's what we should learn from ants.
检验二氧化碳的方法是( )
函数y=cos2xcosπ5-sin2xsin6π5的递增区间为( )