Rewrite the following sentences as required. (根据所给要求，改写下列句子，每空格限填一词)
小题1:Lily had a good time during her stay in Beijing. (改为否定句)
Lily ________ ________a good time during her stay in Beijing.
小题2:We have a class meeting once a week. (对划线部分提问)
_________ _________ do you have a class meeting?
小题3:Many countries make laws to stop smoking in public. (改为被动语态)
Laws _________ _________ by many countries to stop smoking in public.
小题4:The river pollution is serious in our country today. (改为感叹句)
_________ _________ the river pollution is in our country today!
小题5:Robert is so short that he can’t yet reach the pears on the table. (改为简单句)
Robert isn’t _________ _________ to reach the pears on the table.
小题6:I can’t give you better advice than that. (保持原句意思)
I can _________ give you _________ advice.
小题7:Bill didn’t go to bed until he finished writing the letter at 11:45 last night. (保持原句意思)
Bill _________ _________until he finished writing the letter at 11:45 last night.
小题1:didn’t have
小题2:How often
小题3:are made
小题4:How serious
小题5:tall enough
小题6:only... that
小题7:stayed up
小题1:行为动词一般过去时的否定用didn’t + 动词原形，所以填入didn’t have.
小题2:对动作频率的提问用How often.故填入How often.
小题3:被动语态的结构为be + 过去分词，主语为laws,所以填入are made.
小题4:感叹句的常用句型：What a / an + adj. + n + (主语 + 谓语动词)!以及How + adj. / adv. + 主语 + 谓语动词! 所以填入How serious.
小题5:原题意为：Robert个子很矮，以致他够不着桌子上的梨子。改写后则用be enough to do sth.的结构。故填入tall enough.
小题6:原句意为：我不能给你比这更好的建议了。也就是说：我只能给你这样的建议。所以填入only... that.
小题7:原题意为：比尔昨晚直到11:45写完信后才睡觉。改写后可用stay up(不睡觉；熬夜)，所以填入stayed up.