同学你好，该知识点来自沪江网校《英语零基础直达大学六级【开学季特惠班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
and不影响时态的，前后时态可以不同。比如
He went to his house and they were having lunch. 他去了他家，他们正在吃饭。
前半句是一般过去时，后半句是过去进行时。


Late in the afternoon, the boys put up their tent in the middle of a field.
快到傍晚的时候,孩子们在田野中央搭起了帐篷。
in the middle of 表示“在...中间、在...当中”，既可以用于表示地理位置，又可以表示时间或在某个过程当中：
Mary was in the middle of reading when her aunt arrived.
玛丽的姑妈达到时，玛丽正在读书。

They told stories and sang songs by the campfire.
他们就围在营火旁讲起了故事，唱起了歌。
介词by表示“在...旁边、靠近...”,通常指距离非常近：
Come and sit by me. 过来坐我旁边。

...the food smelled good 饭菜散发出阵阵香味。
smell在此处是系动词，意思是“闻起来...”,后面的good是形容词做表语。

But some time later it began to rain. 但过了一阵，天下起雨来。
副词later表示“后来、以后、过后”：
He told me he would come again later.
他告诉我他以后会再来的。

The boys felt tired so they put out the fire and crept into their tent.
孩子们感到很疲劳，于是他们扑灭了篝火，钻进了帐篷。
a) 主句The boys felt tired 是主系表结构的句子。feel在这里也是系动词，后面的tired是表语。
b) so they put out the fire and crept into their tent 是结果状语从句。


The stream wound its way across the field and then flowed right under their tent.
那条小溪弯弯曲曲穿过田野，然后正好从他们的帐篷底下流过去。
right在此处表示强调，意为“正好、恰恰、就”。这种用法多用于口语中：
I met him right here. 我就是在这见到他的。



祝同学学习进步~