be was that在句子中为什么出现。done是什么?什么时候可以省略。lt什么情况在句子前?例:lt must perter.例lt upset him that his father was ill.
为什么加系动词be?例lt must be peter.
英语人才,回去好好看看书吧
◑▂◑还想采纳你来着,看书能知道我还问