不是说let后不加s的,为啥新概念第二册59课里：Then he sits and barks until someon

不是说let后不加s的,为啥新概念第二册59课里：Then he sits and barks until someon He sits down and had a test,还是把sits的s去掉? the man looks___first,and then he sits down 新概念英语第二册第五课 up to now 自学导读里说 up to now =still now =until now Let's have strawberries and apples then 的否定句 He sits _____the bus _____ten minutes.let's have a p___in Ci 在新概念第二册62课里的一个句子 新概念第二册里的英语题 求“let’s clean their room first and then ours ”的中文意思?要标准答案噢. not until then后面为什么加过去式不是过去完成式?then的时态不是过去式嘛? 单句改错:Let's put off the meeting until,then we will have time Let's have strawberries and apples then.翻译