A:①②
B:②③
C:③④
D:①④
Look at the man over there.He is hands at us.
下图为我国某地农业生产活动场景图。读图,回答。该地区农业生产( )
设常数a∈R,集合A={x|(x﹣1)(x﹣a)≥0},B={x|x≥a﹣1},若A∪B=R,则a的取值范围为( )