If Ahmad hadn't eaten three bars of chocolate,he wouldn't have had a toothache,and he could have slept at night.
If Joe hadn't played computer games unitl 10 at night,he wouldn't have been late for the bus and wouldn't have missed the shcool trip to the zoo.
if Ms.Harris hadn't climbed the ladder,she wouldn't have fallen and broken her leg and she could have played golf.
祝你科学如意!