1.enlarge的基本意思是使某物变大,可指事物的体积、面积、容量、范围等,也可引申指人扩大其兴趣领域或活动范围等。
2.enlarge可作及物动词和不及物动词使用,作不及物动词时,后接on或upon,可表示详述某事; 用作及物动词时后接名词或代词作宾语。enlarge可用于被动结构。

enlarge on〔upon〕(v.+prep.)
进一步详细论述(问题等) speak or write more about (sth such as a subject)
▲enlarge on〔upon〕 sth
I should like to enlarge a bit on this point.关于这一点我还想多说几句。
Please enlarge on this question, we need to know more.请再详细谈谈这个问题,我们需要多了解一些。
He enlarged on the importance of studying English.他详细地讲了学习英语的重要性。
She enlarged on her favourite subject.她滔滔不绝地谈着她得意的问题。

用作不及物动词
▲S+～(+A)
This photograph won't probably enlarge well.这张照片放大出来很可能效果不好。
The balloon enlarged as we pumped air into it.那个气球充气后就变大了。
His interests have recently enlarged.近来,他的兴趣更加广泛了。
用作及物动词
▲S+～+n./pron.
Do you enlarge photographs?你会放大照片吗?
The newspaper enlarged its editorial staff by engaging two new people.那家报纸雇用两位新人,从而扩充了编辑人员。
Bryce's Department Store enlarged its furniture department about a year ago.布赖斯百货公司大约在1年前扩充了其家具部。
I want to enlarge the lawn.我要扩大草坪的面积。
The successful investment enlarged his personal fortune.成功的投资增加了他的个人财产。
Travel enlarges the mind.旅行增长见识。
We enlarge our views by reading.我们通过读书来开阔眼界。
◇ 用于be ～ed 结构
The dictionary has been enlarged to 500 pages.这部词典扩充到500页。

enlarge, amplify, augment, increase, magnify
参见increase条。