谁知道 He was Jack who helped me out when I was in trouble 哪里错了?

谁知道 He was Jack who helped me out when I was in trouble 哪里错了?
谁知道 He was Jack who helped me out when I was in trouble 哪里错了?

谁知道 He was Jack who helped me out when I was in trouble 哪里错了?
改为：It was Jack who helped me out when I was in trouble .这属于强调句型,强调了主语Jack,非强调的为：Jack helped me out when I was in trouble .