it must be terrile to eat ice cream in summer 这里it must be 是什么句型?表示什么意...it must be terrile to eat ice cream in summer 这里it must be 是什么句型?如何运用

it must be terrile to eat ice cream in summer 这里it must be 是什么句型?表示什么意...it must be terrile to eat ice cream in summer 这里it must be 是什么句型?如何运用
it must be terrile to eat ice cream in summer 这里it must be 是什么句型?表示什么意...
it must be terrile to eat ice cream in summer 这里it must be 是什么句型?如何运用

it must be terrile to eat ice cream in summer 这里it must be 是什么句型?表示什么意...it must be terrile to eat ice cream in summer 这里it must be 是什么句型?如何运用
it 是形式主语,真正的主语是to eat ice cream in summer的不定式.英语中当不定时作主语时常用it来代替以避免头重脚轻.must be表示推测,肯定是的意思.

must be表推测,作谓语,must 表示推测度很强

it 做形式主语，无实意，避免头重脚轻