问题 选择题

设集合M={x|0<x≤3},N={x|0<x≤1},那么“a∈M,是“a∈N”的[ ]

A.充分不必要条件

B.必要不充分条件

C.充要条件

D.既不充分也不必要条件

答案

答案:B

单项选择题
问答题

读图,分析回答:

(1)从图中提供的信息分析,舟山渔场发展海洋渔业的有利条件。

                                                                                                                                                              

                                                                                                                                                              

(2)结合已学的气候和地形知识分析:A(长芦盐场)、B(布袋盐场)两个盐场的成因有什么不同?

                                                                                                                                                              

                                                                                                                                                              

(3)盐是制碱的原料,请说说天津发展制碱的有利条件吗?