①挫败感会带来不舒服、不愉快的负面感受

②挫折也是人生的一部分，要善于面对挫折

③挫败感是无法消除的，只能任其影响自己  ④某些负面情感体验对我们的成长也有意义

若2x²y^2b+3与 $\frac{1}{2}$ x^a+1y ${}^{\frac{2}{3}b-1}$ 是同类项，求a，b的值．

根据所给词的适当形式、音标或语境的提示，完成短文。

      Long long ago, people lived in a clean world. There were no modern ____ (machine). The air was fresh. However, life today has ____ (bring) many new problems. One of the ____ (big) is the environmental pollution. Noise pollution makes us hear more loudly and get ____ 'æŋɡri more easily. Light pollution is ____ (harm) to birds. Air pollution is the most serious ____ ( kaɪnd) of pollution. It is bad for all living things.

      Now, in order to protect our world, we need to do some important things. For ____, we should use both sides of paper and reuse plastic bags. Everyone should care for ____ waɪld animals and plant more trees. Of course, easier said than done. ____ (action) speak louder than words. If everyone knows the ____ (important) of protecting the environment, the world will become more beautiful.