The doctor insisted that the boy_____seriously ill and that he _____on at once.

Mom called me yesterday, asking me _____ I was getting along well with my English study this term.

_____ your letter, I would have written back two days ago. [ ]

依次填入下面一段文字横线处的语句，衔接最恰当的一组是(　　)喜剧有时也被称为滑稽剧，________，________。________：________；________。________，或者说，是一种严肃的喜。①滑稽剧源自人们生活中的小错误、不成功的事情，而喜剧却源于两种社会力量的冲突，表现旧的、假的、丑的、恶的一方的失败的本质②滑稽剧主要是善意的戏谑、讥讽和批评，喜剧却是毫不留情的揭露、批判和犀利、辛辣、痛快的嘲讽③因而会引人发笑④但喜剧与滑稽剧还是有着明显的区别的⑤因此，喜剧比滑稽剧更具严肃性⑥这是因为喜剧中存在着滑稽因素，如行为或语言的乖僻、夸张、倒错、变形及明显的虚假和假作正经、自相矛盾等

ain was ten minutes late , so I_______ have run all the way from my house to the station.