answer:You’ve got the “rule” wrong! There are 4 types of conditional structure in English [If + S + present structure] [,] [S + present structure] = 0 conditional. [If + S + present structure] [,] [S + modal structure] = 1st conditional. [If + S + past structure] [,] [S + modal verb + verb] = 2nd conditional [If + S + past perfect structure] [,] [S + past modal structure] = 3rd conditional. [If + S + past perfect structure] [,] [S + modal structure] = mixed conditional. Your example 2 does not really follow one of the four main patterns – think of it as a pst 0 conditional. Of course, the rules to conditional structureas are simplifications, but the five patterns above are common examples.