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【全额奖学金班】》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~
They have never smoked before, so they were curious to smoke cigarettes.
have改成had，curious about smoking 对抽烟很好奇

That day, the boys took two cigarettes into their pocket from their father's packet.
按照顺序来说That day, the boys took two cigarettes from their father's packet and put them in their pockets.

Then they went and hid in the garage.
went to hide in the garage 躲到车库里去了

Then they were coughing for a long time.
were coughing改成coughed，这里没有必要强调正在进行

What a terrible feel!
应该是It felt terrible.

The father saw smoke coming from the garage so rushed down it.
so后面加从句的主语he，it去掉

He was smiled when he saw the boys smoking.
was是多余的，去掉

He wanted to let them suffer so offered them cigars and the boys accepted the cigars.
改成 He wanted to make them suffer, so he gave them cigars, and the boys accepted them.
make sb…使某人……

That time they thought that smoking is not really a good thing!
改成At that moment, they realized that smoking is not really a good thing.
realize 意识到

祝同学学习进步~