--------------------------------------------------------------------------------------------------------------------------------来源见图片水印
business:这里表示行业
be about:从事
lightly：
"Once a detective, always a detective," he said lightly.
“一日为侦探，终生为侦探，”他满不在意地说。
Despite his bulk he moved lightly on his feet.
尽管他身形庞大，移动起来还是很灵巧。
light：（说话方式）随意的，不严肃的If you say something in a light way, you sound as if you think that something is not important or serious.
Talk to him in a friendly, light way about the relationship...
用友好随意的方式跟他谈谈这一关系吧。
Let's finish on a lighter note.
最后，我们谈一个比较轻松的话题吧。