1.This produced a chain reaction, which made it possible for life to develop.
这就形成一个连锁反应,使生命发展成为可能。
本句中 it做形式宾语,真正的宾语为不定式短语 for life to develop。it做形式宾语还可以代替动名词或从句。
①He thinks it his duty to help others.
他认为帮助别人是他的职责。
②He made it a rule to get up at six every morning.