如果你想要蔬菜和鸡蛋时，你会说：“       ”

活性炭具有吸附作用，经过活性炭净水器过滤的天然水，不能达到(    )

先化简，再求值：（$\frac{a+2}{a^2-2a}+\frac{8}{4-a^2}$）÷$\frac{a-2}{a}$，其中a=2sin60°﹣2tan45°．

    A high school history teacher once told us. “If you make one close friend in school, you will be most fortunate. A true friend is someone who stays with you for life.”1teaches that he was right. Good friendship is just not easily2.

    It is possible that we simply do not stay in one place long enough for3friendship to4. However, there can be5disagreement on the need for each of us to think carefully about the kind of friendship we want.

    To most of us, friendships are considered very important, but we need to have it clear in our6what kinds of friendship we want. Are they to be close or7at arm's length? Do we want to 8ourselves or do we want to walk on the surface? For some people, many friendships on the surface are 9enough—and that' s all right. But at some point we need to10that our expectations are the same as our friends' expectations. The sharing of11experience 12 our tears as well as our dark dreams is the surest way to deepen friendships. But it 13be undertaken(进行) slowly and carried on only if there are14of interest and action in return.

    What are some of the15of friendship? The greatest is the attraction to expect too much too soon. Deep relationships16time. Another “major difficulty" is the selfishness to think one “possesses" the other, including his time and attention. Similarly, friendships17actions in return. In18words, you must give as much as you take. Finally there is a question of taking care of. Unless you spend19time together, talking on the phone, writing letters, doing things together, friendships will die 20

例如：

Jill is good at the high jump.