So let’s say that you’re sitting at a restaurant and when your food arrives, you take one bite and decide that something is preventing you from taking a second bite. No matter what the reason is, this dish is going back to the kitchen, and now it’s up to you to find a way to send it back politely.

First of all, the single most important thing to do when you’re sending something back is to do it immediately. If you eat half the dish before sending it back, the server and kitchen will believe that you really don’t need to send it back.

If a dish is too salty that it cannot be eaten, you should first let the server know what the situation is, and they’ll take it back to the kitchen and bring you a new one. Remember that it is not the server’s fault, so don’t take it out on them. Also, don’t be afraid that they’ll get angry at you, or someone will spit (吐) in your food. It’s their job to make sure that you’re satisfied, and if the kitchen clearly makes a mistake the server will be frustrated with the kitchen, not with the diner who has been served an inedible meal. A new dish will be cooked, and nobody’s going to spit in it.

There is, however, one example when you are sending back a dish which will really annoy both the server and the kitchen. If you order a pasta dish that contains pancetta but then send it back to the kitchen because you’re a vegetarian (素食者) and don’t know what pancetta is, and then congratulations because you’re one of the most unbearable types of customers a restaurant can have. A perfectly good plate of food is just thrown out because you don’t ask what pancetta is before ordering.

So the bottom line: Use common sense if you think that you need to send your dish back. If the kitchen do something wrong, then they’re on the hook for a new plate of food. If you do something wrong, then hopefully you’ve learned a lesson.

   Good learners can inspire students or anybody to learn well. Here are some characteristics of good learners.

Good learners are curious. They wonder about all sorts of things，often about knowledge beyond their areas of expertise（专长）. 【小题1】 Finding out about something they didn't know satisfies them for the moment，but their curiosity is addictive.

Good learners don't give up easily. A few things may come easily to learners but most knowledge arrivesafter effort. Good learners are willing to put in time. They try to search out new information. They read，analyze，and evaluate（评估）the information they've found. 【小题2】

Good learners know that a lot of learning isn't fun. The journey to understanding generally isn't all that exciting. 【小题3】 Others need boring attention to detail，and still others need periods of intense mental focus. Your back hurts，your arms and legs get tired，and your coffee gets cold.

【小题4】 There's always more to know. Good learners are never satisfied with how much they know about anything. They are surrounded by questions — the ones they still can't answer, or the ones without very good answers. Those questions follow them like day follows night with the answers bringing daylight.

Good learners share what they' ve learned. Good learners are teachers committed to sharing with others what they' ve learned. 【小题5】 Good learners can also explain what they know in ways that make sense to others. They are connected to the knowledge passed on to them and committed to leaving what they' ve learned with others.

   A strong memory depends on the health and vitality（生命力）of your brain. They say that you can't teach an old dog new tricks，but when it comes to the brain，scientists have discovered that this old saying simply isn't true. 【小题1】

Give your brain a workout. Memory, like muscular strength, requires you to“use it or lose it”. The more you work out your brain, the better you' ll be able to process and remember information. 【小题2】

Don't skip the physical exercise. While mental exercise is important to brain health, that doesn't mean you never need to break a sweat. Physical exercise helps your brain stay sharp. It increases oxygen to your brain and reduces the risk of disorders that lead to memory loss.

Get enough sleep. There is a big difference between the amount of sleep you can get now and the amount you need to function at your best. 【小题3】

Keep stress in check. Stress is one of the brain's worst enemies. Over time, stress destroys brain cells. Studies have also linked stress to memory loss.

Have a laugh. 【小题4】 That holds true for the brain and the memory, as well as the body. Unlike emotional responses, which are limited to specific areas of the brain, laughter involves multiple regions across the whole brain.

【小题5】 Just as the body needs fuel, so does the brain. You probably already know that a diet based on fruits, vegetables, whole grains,“healthy”fats and lean protein will provide lots of health benefits, but such a diet can also improve memory. For brain health, though, it's not just what you eat — it's also what you don't eat.