如图三是肾单位结构模式图，请据图回答：

（1）血液从____ ____ 滤过到____ ____ 成为原尿．

（2）原尿经过____ ____ 的____ 作用，形成尿液．

（3）与3内液体相比，6内液体不含____ ．

（4）与原尿相比，尿中不含____ ，因为____ ．

（5）尿的形成包括____ 、____ 和____ 三个过程．

（6）图中流动脉血的结构序号是____ ．

（7）肾单位中血液由动脉血变静脉血是在____ ．

    Alan, a boy from India went to study in the UK two years ago. He1 a part-time job in a restaurant. Many British students also worked there. Their job was2 the dishes. It was an easy job, but the boss said, "You must wash every dish seven3 ."At first, Alan was 4 . The boss was happy with him. After one month, he found that the boss didn't check very often. He thought there was no5between five times and seven times. Then he just washed five times. So he worked very6 . The boss was even happier. One day, a British student asked him7 he could wash so fast. Alan told him the secret. The British student was surprised but didn't say8 . A few days later he told the boss about it. The boss fired(解雇)Alan. Alan had to go to other9, but all of them said, "Go away! You are not10 .

    We don't need you. Alan was sad because he could do nothing.