题目

取两粒菜豆种子，放在适宜的条件下使其萌发。等幼苗发育到一定时期，切去其中一株的根尖。几天后发现被切去根尖的幼根不再生长，另一株幼苗的幼根却生长得很快，这是由于根尖中（） A . 根冠和分生区不断增加新细胞 B . 根冠增加新细胞，伸长区细胞不断伸长 C . 伸长区细胞不断伸长 D . 分生区细胞进行分裂，伸长区细胞不断伸长 (完形填空) A 　(1)　way to pass an exam is　(2)　hard every day of the year. You can’t succeed(成功)in 　(3)　exam if you are lazy for　(4)　of the year and then work hard only a few days before the exam. You should go to bed early before a few days you have the exam. Don’t stay up late　(5)　night. When you start the exam, you should read the question paper　(6)　. Before you hand in the test paper, check your　(7)　. Correct(改正)the mistakes(错误)if there are　(8)　and make sure(确信)that you　(9)　all the　(10)　in the paper.(1) A. well B. good C. short D. long [　　] (2) A. worked B. working C. to work D. works [　　] (3) A. an B. a C. / D. one [　　] (4) A. many B. more C. less D. most [　　] (5) A. at B. to C. down D. on [　　] (6) A. careful B. care C. careless D. carefully [　　] (7) A. questions B. watch C. answers D. pens [　　] (8) A. a B. any C. the D. one [　　] (9) A. answer B. answered C. to answer D. answering [　　] (10) A. answers B. questions C. teachers D. boys [　　]