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."_1_ teaches that he was right. Good friendship is just not easily _2_.
It is possible that we simply do not stay in one place long enough food _3_friendship to _4_. However, there can be_5_disagreement 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 clear in our _6_ the kinds of friendship we want. Are they to be close or _7_ at arm's length? Do we want to _8_ourselves or do we want to walk on the surface? For some people, many friendships on the surface are _9_enough—and that' s all right. But at some point we need to 10 that our expectations are the same as our friends' expectations. The sharing of_11_experience _12_ our tears as well as our dark dreams is the surest way to deepen friendships. But it _13_be undertaken(进行) slowly and carried on only if there are _14_of interest and action in return.
What are some of the _15_of friendship? The greatest is the attraction to expect too much too soon. Deep relationships _16_time. Another“major difficulty" is the selfishness to think one “possesses" the other, including his time and attention. Similarly, friendships _17_ actions in return. In 18words, you must give as much as you take. Finally there is a question of taking care of. Unless you spend _19_time together, talking on the phone, writing letters, doing things together, friendships will die _20_.
1. A. Knowledge B. Teachers C. Experience D. Parents
2. A. understood B. formed C. realized D. produced
3. A. true B. common C. deeply D. actual
4. A. design B. intend C. develop D. appear
5. A. no B. some C. any D. none
6. A. hearts B. thoughts C. actions D. minds
7. A. remained B. left C. kept D. stayed
8. A. own B. owe C. share D. spare
9. A. that B. very C. quite D. not
10. A. make sure B. remember C. expect D. check out
11. A. social B. ordinary C. good D. personal
12. A. includes B. to include C. including D. included
13. A. can B. need C. will D. must
14. A. marks B. sights C. scenes D. signs
15. A. difficulties B. differences C. advantages D. things
16. A. cost B. spend C. ask D. take
17. A. require B. request C. depend D. suggest
18. A. some B. many C. other D. different
19. A. reasonable B. comfortable C. less D. a lot
20. A. for B. away C. out D. from
g的加速度向下运动，则R是r的几倍？
（2）3
，E＝
Ba2ω. 2分
＝m·
g， 2分
·R，解得
＝3. 2分