是主语从句。例如 lt is&nbsp good that we are going to play football next Monday.(下周一我们去踢足球太好了。)&nbsp &nbsp &nbsp &nbsp这个句子的it从形式看是主语，实际上它只是代替后面that引导的从句，这个从句才是真正的主语(主语从句)。这是因为主语从句作主语太长，放在前面显得头重脚轻，才用it代替它。 ...