A poor farmer had a friend,who was famous for the wonderful apple he grew.One day,his friend gave the farmer a young apple tree and told him____(take) it home and plant it.

    The farmer was pleased with the gift,but when he got home he did not know where to plant it.He was afraid that ____he planted the tree in one of his fields,his neighbors would come at night and pick some of the apples.Finally he planted the tree in his wood____no one could see it.But____sunlight and good soil,the tree soon died.

    Later the friend asked the farmer why he had planted the tree in____a poor place."What's the difference?"the farmer said____(angry)."If I had planted the tree near the road,strangers____(steal) the fruit."

    "Yes,"said the friend,"____at least someone could have enjoyed the fruit.Now you not only have robbed everyone____the fruit,but also you____(destroy)a good apple tree!"

20910000000≈____亿

1597000000≈____亿

默写填空。
①为什么我的眼里常含泪水？          。
②         ，再而衰，三而竭。
③苏轼在《江城子密州出猎》中引用典故，表达希望得到朝廷重新重用的句子是：“           ，             ”。
④炎炎夏日，当你看见农民仍然头顶烈日，在田地里辛勤劳作时，你不禁心生感慨，这时，你可能会吟出“         ，         ”这两句诗来表达此情此景。
⑤老骥伏枥，       。(曹操《龟虽寿》)
⑥长风破浪会有时，       。(李白《行路难》)
⑦      ，帘卷西风，人比黄花瘦。(李清照《醉花阴》)
⑧江山代有才人出，       。(赵翼《论诗》)

如图所示，A的重力是40N，如滑轮、弹簧测力计和绳重均不计，在滑轮组静止时，a、b、c弹簧测力计的读数各为　 ____N、　 ____N、　 ____N．