1是李明帮助的我 It was Li Ming who/that helped me.
2李明帮助的是我 It was me whom/that Li Ming helped.
3李明是在公园帮助的我 It was in the park that Li Ming helped me.
1是李明帮助的我 It was Li Ming who/that helped me.
2李明帮助的是我 It was me whom/that Li Ming helped.
3李明是在公园帮助的我 It was in the park that Li Ming helped me.