设变量x，y满足约束条件$\left\{\begin{array}{c}2x+y-2\ge 0\\ x-2y+4\ge 0\\ x-1\le 0\end{array}\right.$,则目标函数z＝2y－3x的最大值为(    )

能够消化淀粉的结构是下列哪一组（  ）

阅读短文，根据短文内容及首字母提示，在空白处填入一个适当的单词。
      Think about two people you know. How would you describe their personalities? Are they the  s ____  ?Of course not! Everyone is different .Even twins have  d ____ personalities.
    Some people are very outgoing and  f____  .They like to be  w____  other people all the time. And some people are quiet, maybe even shy. They like to be alone or play with a  f____   friends.
    Some people worry a lot. They may  w ____ about many things.  H____ ,some people don't worry about anything! They  n____ mind what is going on next. These people are very relaxed.
    Some people are h____ .They always do their best. They aren't lazy. They always get more chances to have success.
And don't  f ____  this: Everyone is different. That means you are special.