给出下列命题：①sin（-10）＜0；②函数y=sin（2x+5π4）的图象关于 发布时间：2017-04-14 17:30 │ 来源：www.tikuol.com 题型：填空题 问题： 给出下列命题：①sin（-10）＜0；②函数y=sin（2x+5π4）的图象关于点(-π8，0)对称；③将函数y=cos（2x-π3）的图象向左平移π3个单位，可得到函数y=cos2x的图象；④函数y=|tan(2x+π4)|的最小正周期是π4．其中正确的命题的序号是______．
题型：填空题 下列说法正确的是（ ）A．使用含氟牙膏可预防龋齿B．人若缺锌元素，会引起贫血C．99.999999999%的高纯硅通常认为是纯净物D．某物质与NaOH溶液反应生成盐和水，则该物质一定是酸 查看答案
题型：填空题 完形填空。 Jenna, a popular girl from Westwood Middle School, had graduated first in her class and was ready fornew 1 in high school. 2 , high school was different. In the first week, Jenna went to tryouts (选拔赛) for cheerleaders (拉拉队队员). She was competing against very talented girls, and she knew it would be 3 for her to be selected. Two hours later, the 4 read a list of the girls for a second tryout. Her heart 5 as the list ended without her name. Feeling 6 , she walked home carrying her schoolbag full of homework. 7 home, she started with math. She had always been a good math student, but now she was 8 . Shemoved on to English and history, and was 9 to find that she didn't have any trouble with those subjects. Feeling better, she decided not to 10 math for the time being. The next day Jenna went to see Mrs. Biden about being on the school 11 . Mrs. Biden wasn't as enthusiastic (热情) as Jenna. "I'm sorry, but we have enough 12 for the newspaper already. Come back next year and we'll talk then." Jenna smiled 13 and left. "Why is high school so 14 ?" she sighed (叹气). Later in 15 class, Jenna devoted herself to figuring out the problems that had given her so much 16 . By the end of class, she understood how to get them right. As she gathered her books, Jenna decided she'd continue to try to 17 at her new school. She wasn't sure if she'd succeed, but she knew she had to 18 . High school was just as her mom had said, "You will feel like a small fish in a big pond 19 a big fish in a small pond. The challenge is to become the 20 fish you can be." ( )1. A. processes ( )2. A. Therefore ( )3. A. difficult ( )4. A. editor ( )5. A. jumped ( )6. A. strange ( )7. A. Arriving ( )8. A. struggling ( )9. A. ashamed ( )10. A. put up ( )11. A. committee ( )12. A. speakers ( )13. A. widely ( )14. A. similar ( )15. A. physics ( )16. A. pleasure ( )17. A. fit in ( )18. A. swim ( )19. A. in return for ( )20. A. slimmest B. decisions B. However B. easy B. boss B. sank B. happy B. Arrived B. improving B. disappointed B. prepare for B. newspaper B. readers B. weakly B. ordinary B. history B. hope B. look up B. try B. in case of B. smallest C. challenges C. Otherwise C. boring C. candidate C. stopped C. unhappy C. To arrive C. working C. shocked C. worry about C. radio C. cheerleaders C. excitedly C. different C. English C. trouble C. stay up C. ask C. in terms of C. best D. exercises D. Besides D. interesting D. judge D. raced D. lonely D. Arrive D. complaining D. pleased D. give up D. team D. writers D. brightly D. familiar D. math D. sorrow D. get up D. escape D. instead of D. gentlest 查看答案