The Second Conditional refers to an unreal (or very unlikely) situation in the PRESENT time. The most confusing thing about the second conditional is that we use the PAST TENSE in the "if" clause, even though we’re referring to the PRESENT! Consider the following examples:

• I am very busy (and very broke). As I’m sitting here in front of my computer, I’m thinking about taking a trip to South America. It would be really nice to go to the airport and get on a plane right now. However, this is completely impossible! I can express this by saying, "If I had the time, I would go to South America." (I could also say, "If I had the money, I would go to South America.")

• My friend John is always talking about how expensive restaurants are. He never goes to the grocery store and his kitchen cupboards are always empty. One day he starts complaining again. I say, "John, if you learned how to cook, you wouldn’t need to eat out all the time." (It is highly unlikely that John will learn how to cook.)

Okay, now that you understand that the PAST TENSE in the "if" clause refers to the PRESENT time, there is one other rule you should be aware of. (You will hear native speakers break this rule, but you should use it—especially in formal speech and formal writing.) If the main verb in the "if" clause is "be," we use "were" with ALL subjects, including first and third person singular. (This is the subjunctive mood.) Consider the following examples:

• "If I were rich, I would travel around the world." (UNREAL: I’m not rich.)
• "If I were President, I would give everyone free health care." (Obviously UNREAL: I’m not President.)
• "If I were you, I would study hard." (Obviously UNREAL: I’m not you.)
• "If Napoleon were alive today, he would be fighting a war." (UNREAL: Napoleon is dead.)
• "If my brother were here, he would buy me a beer." (UNREAL: My brother is in Costa Rica.)

The Third Conditional refers to an unreal situation in the PAST. In other words, it refers to something that did NOT happen in the past, though maybe it was once an option. The most confusing thing about the third conditional is that we use the PAST PERFECT in the "if" clause, even though we’re referring to the PAST. Consider the following examples:

• My friend Liz likes this guy named Joe. Last week I had a party. Joe came to my party. Liz’s parents were in town so she went out to dinner with them. She did not come to the party. I tell her, "Too bad. If you had come to the party, you would have seen Joe."

• I took three weeks off work in January. Since I didn’t get paid for my time off, I don’t have any extra money right now. I can express this by saying, "If I hadn’t taken that time off, I would have more money."