这是我在BBC看到的文章，里面的一小段
Gone are the days when all men had to think about was wearing a nice suit to
be smart and handsome.
我大概知道gone are the days是倒装
不倒装:The days when all men had to think about was wearing a nice suit to
be smart and handsome are gone.
翻译感觉是 "人们必须思考是否穿着合适的衣服让自己看起来聪明和帅的日子已经过了"
我不懂的是think about 后面为什么可以加 was wearing?
思考了很久，还是没找出头绪，不好意思，感谢大大帮忙~

all "that" men had to think about was

不好意思，还是不太了解~

all [men had to think about] was [wearing a nice...]

这是fixed expression，句型固定。你可以用Google找"cleft sentences" http://tinyurl.com/mt5fnlf (打底，然你再继续找)All men had to think about | was | [something] (多种句型之一) [wearing a nice suit to ... handsome](整个是'动名词词组')就是那个something

男人们只需要穿上一件漂亮西装就能让自己看起来精明又英俊的时代已经过去了

这种高级的句型要在什么文法才会看得到？gone are the days....形容词开头的倒装句有时也不太懂怎么用

真的非常谢谢各位~dunchee你的解释很精辟~谢谢