综合写作：
Passage:
ocean life extinction. 原因有三：气候变冷导致海平面下降;小行星撞击地球;太阳紫外线加强由于臭氧层消失，给了个例子，一种海洋生物那时候在海洋表面绝迹了。
Lecture: 反驳
1 气候变冷很缓慢而且海平面下降晚于extinction
2 没发现那个时期的crater。
3 那种海洋生物具体在哪生活我们不知道，可能在海底生活。
独立写作：
三选一，你愿意作出下列那种改变improve your health
Out of the following three things, which one would you prefer to regulate in order to improve your health?
1. The kind of food you eat
2. The amount of exercise
3. The amount of stress in your life
Modern society has turned humans into curious creatures. Our ancestors were highly active thanks to their hunter-gatherer lifestyle; they ate fairly balanced diets due to the limited availability of fats and simple carbohydrates; and they relied on stress as a survival mechanism that kept them alert during intermittent periods of danger. Now, many of us spend upwards of 8 hours a day sedentary at our jobs; we eat unbalance diets of pre-prepared foods in order to save time; and we are constantly stressed due to a never-ending bombardment of stressors coming from our contemporary lifestyle. Managing all three things--diet, exercise, and stress--would be a daunting task for anyone, so if I had to pick one thing to improve my health, it would probably be exercise.
To begin with, exercise is much easier to manage than both your diet and your stress. In order to manage your diet effectively, need to reduce or eliminate certain foods you enjoy eating, as well as create a comprehensive plan that balances your intake of different nutrients like proteins, fats, and carbohydrates. This is too much for most people, which explains the prevalence of "fad diets" that involve, for example, only eating a single type of food; these diets rarely ever work, and can even be dangerous. Managing stress is similarly difficult, because there are so many potential stressors to account for (work, kids, bills, etc.) and it may not be plausible to try and manage all of them. Exercise, on the other hand, can be effective even when simple. Take running: This exercise requires no forethought and can be done pretty much everywhere by pretty much everyone, yet carries a laundry list of health benefits ranging from boosting the immune system to lower the risk of breast cancer.
Also, exercise has the scientifically measurable benefit of improving mood. When we perform physically demanding activities such as running, the brain releases a rush of endorphins that produces feelings of euphoria. From an evolutionary perspective, this is a neurological reward that encourages us to run and be healthy--we're basically built to be runners. If you can incorporate running (or some similar form of exercise) into your weekly routine, you'll notice your mood improve almost immediately. And there's also another, indirect way exercise improves mood: When you're fit, you feel much better about yourself. I don't just mean in the narcissistic way, either--knowing that you're exercising is just a good feeling.
Lastly, and perhaps most importantly, exercise can lead to both better eating habits as well as lower overall stress. Exercise is in fact an excellent way to manage stress, and is recommended by medical authorities as a way to strengthen the brain's buffers against it. It is even recommended by doctors for treating depression. This stress reduction from exercise can in turn lead to better food choices, since stress is an major contributor to poor eating habits, and eating healthy is much easier when you're feeling good about yourself. Anyone who's reached for junk-food during a stressful situation can tell you that.
Obviously, diet, exercise, and stress management are all important for living a healthy life. However, if you had to choose only one, I'd say that exercise wins out when it comes to getting the most bang for your buck.
