I don't know how is was that he narrowly escaped being killed in the earthquake.

这的确是个强调句,强调的是how没错,强调他是如何在地震中幸存下来.
is was that的部分应该是打错了,正确的应该是it was that才对.否则is 和was两个be动词不能直接连用的.这个强调的是整个宾语从句吗？我觉得强调的应该就是how，强调句通常强调的都是句子的某个成分，而不是整个句子。 比如 It was he who won the game. 强调的就是he。如果换成疑问句的话是：Who it was that won the game. 强调的就是who咯。谢谢了，我明白了。