iqrozen.blogspot.com | Indonesian students usually study about Conditional Sentences in yunior or senior high school. The order of the two clauses is flexible, it’s not important. But if the if-clause comes first, it must be followed by a comma. Example : If it rains, I’ll stay at home. There are 4 types of conditional sentences. They are classified according to the degree of probability that they express. Each type of conditional sentences uses different tenses to show the difference in the degree of probability. Read more about English Grammar Degree of Comparison.