I have tried looking in my textbook as well as my notes to figure out how to do this problem. I should have asked my teacher when I had the chance, but first I wanted to try working out the problem myself. I have until Monday to figure out how to do this problem, but would appreciate it if you could help me start. Here's the problem:

Show that the grammar is still ambiguous:

<statement> ------> if exp then <substat> else <statement> (1)
| if exp then <statement> (2)
| other-stat (3)

<substat> ---------> if exp then <substat> else <statement> (4)
|other_stat (5)

I at least know that I have to show two different parse trees of a single statement that fits those rules. Other than that, I'm stuck. Please help.