外教微课是为大家推出的系列网络外教课程。每集配备一个10分钟左右的视频，常听多看，锻炼口语听力，提升语言能力。Students are often told that unless they practice, they won't improve. But if you don't know what 'unless' means or how to use it, you might get the wrong idea.
This grammar lesson focuses on the negative conditional and the consequences that follow. I'll teach you when and how to use 'unless', 'if not', 'as long as', and more.
https://v.qq.com/txp/iframe/player.html?width=500&height=375&auto=0&vid=w06359kk5k3
TRANSCRIPT
Hi, welcome again to www.EngVid.com . My name is Adam. Today's lesson is about "if not", "unless", "as long as", "not". Actually, this is a lesson a few students have requested, because a lot of people get confused with this word "unless".
So that's going to be the focus of our lesson, although to understand this word "unless", you have to understand the "if not" conditional. That's called a "conditional phrase." Before we do anything, we need to make sure that everybody understands how to use the conditional. How to use an "if clause", because sometimes people get confused with this.
Today we're going to focus on a real conditional. Not the past, not the hypothetical, the unreal. We're just going to focus on the real one, because all of this stuff applies to the other ones, as well. So let's start. Before I look into the grammar of it, which is actually important, let me give you a sentence. Next week you have a test, and you come to me for advice as your teacher, and what am I going to tell you. "If you don't study, you won't succeed." "If you study, you will succeed." Very simple, right? So first, we're going to look at how to structure this sentence, because then I want to show you that "unless" basically means the same as "if not".
Okay, so first, to make a real conditional sentence you have your "if". You have your subject. You have your present verb, for example "or". You have "if", subject, and your not present: "If you don't study," and then the second half. Now, the second half could be positive or negative. The second half of the clause doesn't matter, according to what you have here. This will always be the same. It doesn't matter which clause you're beginning with, you're always going to end the same way, because the meaning doesn't change, okay?
But we're going to get into more specifics. "If you study, you will succeed." "If you don't study, you will fail." Or, "If you study, you will not fail." "If you don't study, you will fail." The verb you use here defines which one of these you're going to use. So this is not important. This doesn't change. What we're going to focus on is here. Now the most important thing to remember is that "unless" basically means "if not". You'll notice here I have a positive verb. I have a negative verb. We're also going to look at "as long as", or "as long as not", positive and negative.
With "unless", you're only going to use a positive verb, okay? That's very important to remember. "Unless you study, you will fail. Unless you study, you will not succeed." It's all relative, and "as long as" means the exact same thing as the "if" or the "unless". "As long as you study, you will do well." "As long as you don't study, you won't do well." Very simple. So "if not", "unless", "as long as", "not", basically all mean the same thing. You just have to remember how to structure it, and the structure is almost the same.
What is the most important, do not use "unless" with "not." Then you have a double negative. We all know from our beginner English classes we don't like double negatives, right? Okay, good. Let's look at some examples of actual sentences to see how all of this works. Okay so here we have some sentences. Let's go through each one and I'll make the changes to the negatives, as I go along. "If you quit smoking," for all you smokers out there. "If you quit smoking, you will feel better." "If" + subject + verb - will + verb, positive verb, etc. Or: "If you quit smoking, you won't feel bad." Now what happens if I introduce the negative into the first part? "If you don't..." "If you don't quit smoking" what's going to happen? Or what will happen? "If you don't quit smoking, you'll feel better." Is that true? No. "If you don't quit smoking, you'll feel bad." "If you don't quit smoking, you won't feel good." You made this the negative. You have to change the consequences. You have to change the condition that will happen after this is met. This is the difference, right? "If you don't quit smoking, you'll feel bad." Let's look at this sentence. "Unless you quit smoking, you will feel bad."
Now what's the difference between this sentence and this sentence with a "don't"? Nothing, it's the exact same. Here is the result: "If you don't quit smoking, you will feel bad." Bad and bad, do you understand what I'm saying? The "unless" is the same as, "if you don't". This is what we have to remember here. This is the negative included in the word. Now usually when there's a negative in a word, everybody can understand it. In the word "unless" there's nothing to tell you it's a negative, except maybe the word "less," but not really, right? So you have to be very careful to remember this means "if not". "Unless you quit smoking, you won't feel good." You won't feel good. Same thing, but the "don't" and the "unless" go together, same meaning. "As long as you smoke," now here I have the verb "smoke".
Here I put "quit smoking". I went to the opposite verb, "smoke". "As long as you smoke, you will feel bad." "As long as you don't smoke", what is the consequence? "You will feel good." What do you know, "don't" changes the consequence. "Don't" changes the consequence. "Unless" is the consequence. We don't say, "Unless you don't quit smoking." It's a double negative. It sounds very strange, it feels very strange. We don't use it. We go with this negative, and we have the matching consequence. "Consequence" basically means the result of the action.
Okay, I hope this is pretty clear. Anyway, go to www.EngVid.com . There's a quiz there. You can also ask me questions. Don't forget to check out the video on YouTube as well, and subscribe to my channel, and I'll see you again real soon. Bye. Learn English for free www.engvid.com网络资源，仅供学习交流