2. It was in 1897 that a European… 强调句：it is/was +被强调部分 ＋that +其它 此结构强调的成分限于主语，宾语和状语 It is from the sun that we get light and heat. 我们是从太阳那儿获取光和热。 It was not until I had read your letter that I understood the true state of affairs. 直到读了你的信，我才知道实际情形。