当两商品的价格P均从P1同幅下降到P2时，对于需求量Q的变化，若有如下判断：

①两商品的需求量与价格同向变动

②两商品的需求量与价格反向变动

③两商品相比，商品甲是高档耐用品

④两商品相比，商品甲是生活必需品

其中正确的是

    It's generally believed that people act the way they do because of their personalities and attitudes. They recycle their garbage because they care about the environment. They pay $5 for a caramel brulee latte because they like expensive coffee drinks.

    It's undeniable that behavior comes from our inner dispositions(性情), but in many instances we also draw inferences about who we are, as suggested by the social psychologist Daryl Bern, by observing our own behavior. We can be strangers to ourselves. If we knew our own minds, why should we need to guess what our preferences are from our behavior? If our minds were an open book, we would know exactly how much we care about the environment or like lattes. Actually, we often need to look to our behavior to figure out who we are.

    Moreover, we don't just use our behavior to learn about our particular types of character — we infer characters that weren't there before. Our behavior is often shaped by little pressures around us, which we fail to recognize. Maybe we recycle because our wives and neighbors would disapprove if we didn't. Maybe we buy lattes in order to impress the people around us. We should not mistakenly believe that we always behave as a result of some inner disposition.

    Whatever pressures there can be or inferences one can make, people become what they do, though it may not be in compliance(符合) with their true desires. Therefore, we should all bear in mind Kurt Vonnegut's advice: “We are what we pretend to be, so we must be careful about what we pretend to be.”