it作为形式主语,指代后面的ignore这个动作
it would be dangerous to ignore可以变换一下语序
即:to ignore (the rules) would be dangerous
补充:which作为定语从句的先行词,指代的是前面的the rules
it作为形式主语,指代后面的ignore这个动作
it would be dangerous to ignore可以变换一下语序
即:to ignore (the rules) would be dangerous
补充:which作为定语从句的先行词,指代的是前面的the rules