You start putting two and two together.

你开始把二和二放在一起。

I’m just putting two and two together.

举一反三嘛!

" I expect the old gentleman has been putting two and two together, " said Holmes as we walked hotelward.

“我想老先生一直在把两个和两个放在一起， ” 我们朝旅馆走去时， 福尔摩斯说。

And, since Tisdall betrayed his astonishment and Hopkins his instant putting two and two together, he added, " We're hoping he can help us" .

而且，由于 Tisdall 出卖了他的惊讶， 而 Hopkins 立即将两个和两个放在一起， 他补充说，“我们希望他能帮助我们” 。