通过学习碱的性质，我校化学兴趣小组的同学对实验室的“氢氧化钙是否变质以及变质的程度”展开了探究活动，请你一同参与：

提出问题：氢氧化钙是否变质？

猜想与假设：同学们经过讨论认为样品存在三种可能情况：没有变质；部分变质；完全变质．

“他们号召用现代西方的标准，重新评价中国的文化遗产，乐意地与引致中国衰弱的那些因素决裂……对中国过去引入了一种全面否定的新态度。就深度和广度而言，这场思想变革超过1895—1911年期间的变革。”文中的“这场思想变革”（     ）

函数$f\left(x\right)=lg\left(x+2\right)+\sqrt{2-2^x}$的定义域为（   ）

    If you work hard to have a positive attitude, you might be surprised by how much better you feel about yourself and life in general. ____ The less stress you feel, the better you will feel generally. So if you've been feeling tired, think about the good, put on a happy face and you just might feel better soon.

    But how can you have a positive attitude when life is hard? It's more than just turning life's lemons into lemonade. ____ But it's worth it. Here are some ways you can develop and maintain(保持)a positive attitude even in the midst of life's troubles.

    ____It just means being an optimist and looking for the good in things, rather than being a pessimist(悲观者) and focusing on the bad in things. Sometimes your view can make all the difference in the world.

    Identify(确认) those areas of your life that might not be going so well. ____ Focus on one area at a time and think of ways you can find the positive in them.

    Smile and laugh! Yes, it can be that simple. Learn to love life, no matter what's going on. Smile at others and they will smile back at you.____Sometimes laughter really is the best medicine.

    Exercise！Get off the couch and get moving. Being active and healthy can give you a completely different attitude to life.

A. Have fun and find the humor in life.

B. You may find it hard to stay positive in your life.

C. Having a positive attitude can take some hard work.

D. A positive attitude doesn't mean taking no notice of life's troubles.

E. Having a positive attitude can also reduce your stress level.

F. These are the areas likely to make you think negative thoughts.

G. Go to bed earlier so you get the sleep you need to feel positive.