外研社2024七年级上unit 2选词填空59题较难
Some city people won't live in a village _____1_____ they think that village life is dull and uninteresting. There is nothing to do in a village. They _____2_____ that they couldn'...
第2讲、常用逻辑用语(学生版)
知识梳理 一、充分条件、必要条件、充要条件 1、定义 如果命题“若,则”为真(记作),则是的充分条件;同时是的必要条件. 2、从逻辑推理关系上看 (1)若且,则是的充分不必要条件; (2)若...