<p>This is from a book called "Woe is I."</p>
<p>"Where There's a Will, There's a Would"</p>
<p>Do you waffle when faced with the choice of will or would? Take your pick: Harry said he [will or would] make waffles for breakfast. </p>
<p>Follow the lead of the first verb (said). Since it's in the past tense, use would: Harry said he would make waffles for breakfast. When the first berb is in the present tense (says), use will: harry says he will make waffles for breakfast.</p>
<p>Now here's an example with three verbs (the same principle applies): Harry thought that if he [eats or ate] one waffle, he [will or would] want another.</p>
<p>Since the first verb (thought) is in the past, use the past tense, ate, and would: Harry thought that if he ate on waffle, he would want another. When the first verb is in the present (thinks), use the present tense, eats, and will: Harry thinks that if he eats one waffle, he will want another.</p>
<p>"In the Land of If"</p>
<p>Think of if as a tiny set of scales. When a sentence has if in it, the verbs have to be in balance. When the if side of the scale is in the present tense, the other side calls for will. When the if side of the scale is in the past tense, the other side gets a would.</p>
<p>If he shops (present) alone, he will spend too much.
If he shopped (past) alone, he would spend too much.</p>
<p>Balancing the scales becomes more complicated as the tenses get more complicated. When you use a compund tense with has or have on the if side of the scale, you need a will have on the other side. Similarly, when you use a compound tense with had on the if side of the scale, you need a would have on the other.</p>
<p>If he has shopped alone, he will have spent too much.
If he had shopped alone, he woud have spent too much.</p>
<p>The if part doesn't have to come first, but the scales must stay in balance: He will spend too much if he shops alone. He would spend too much if he shopped alone.</p>
<p>Aren't grammar books wonderful?</p>