請問新概念英語的這句話,是什麼語法結構?

題目：

請問新概念英語的這句話,是什麼語法結構?
新概念英語第三冊第12課里有一句這樣的話「perhaps there is an element of truth in both these picture,but few of us had an opportunity to find out」,這裡爲什麼要用had an opportunity ,而不是have an opportunity.

解答：

我去看了下原文,其實是but few of us have had an opportunity to find out.
用的是現在完成時,表示從過去開始到現在一直都很少有人有機會發現這一點.