If i had paid attention, i wouldnt have hit the tree
if she had enough money, she would be able to buy a new computer
he will have an accident if he does not drive more carefully
if steve hadn't spoken rudely to his boss, he wouldn't have fired him.
if you do not invite her to the party, she will be upset
unless they prepare for the exam properly they will not pass it
he wishes he were taller so he could join a basketball team
if you stayed home tonight, it would be much better
if it rains we will not got on a picnic
he would have done better, if only he had studied more at school (if only he had studied more at school, he would have done better)