根据短文内容选择正确答案。

    A crow(乌鸦) is about twenty inches (英寸) long and black all over. Crows are dirty birds because they live on bad food. Crows eat a lot of waste food. In this way they are more useful to us than any birds. They clean up the dirty things in our streets. Crows are always hungry. They look for food all day, and in the evening you can see them in large numbers flying back to their nests(巢) in the trees. They sleep there at night.

    Crows are much noisier than other birds. Very often a large number of crows will get together on one house and talk. Sometimes they talk together, and sometimes they do it by turns(轮流) like human beings(人类). It is easy to tell(判断) from crow's sound if they are pleased or angry. Perhaps crows talk a lot because they are friendly birds. A pair of crows will live together all their lives, and if one of them dies, the other one becomes very sad and quiet for the rest of its life and some time later it dies too.

多音字组词。

龟：jūn____、guī____

给：gěi____、jǐ____

数：shǔ____、shù____

D

    He Jiang, a postgraduate（研究生）in biology. will become the first Chinese student to give a speech in the commencement(毕业典礼)at Harvard University on May 26, 2016.

    Given the highest honor by the university, He Jiang, who was born in a small village in Hunan province, said, "People in China often believe that it's useless to study and children from the countryside cannot be successful in the future. However, I cannot agree with them. Education can change a person's life. I hope my experience can encourage the students from the countryside to spare no effort in study and make their dreams come true."

    Different from many other families in the village, his parents never thought about finding a job in big cities and leaving their two sons at home without their care. His father was strict about their studies. He and his younger brother studied at home while the other kids in the village played in the fields. Unlike his strict father, his mother took her sons' side when her husband scolded the boys. She preferred to sit with her sons when they studied rather than chat with other women in the village.

    Getting the chance to speak at the commencement is no accident. During his first days in Harvard, it was quite difficult for him to follow the professors in class and he was speechless in campus because of his poor English. Instead of giving up, He Jiang spent all his free time on English. He also made friends with natives to improve his speaking English. One year later, he had little difficulty in class and soon became one of the top students in his class. With the encouragement from Professor Diana Eck. He Jiang decided to apply(申请）for the chance to speak at the commencement.“Few Chinese students had applied before, but I wanted to have a try. I just want to realize my idea of letting more people hear the voice from China and telling them that China is not what it used to be." said He Jiang. After beating three students from Harvard Kennedy School in the third and final round, He Jiang made it to get the chance to speak at the commencement.

    He Jiang will go to Massachusetts Institute of Technology after graduating from Harvard.