如图，已知某船向正东方向航行，在点A处测得某岛C在其北偏东60°方向上，前进8海里到达点B处，测得岛C在其北偏东30方向上，已知岛C周围6海里内有一暗礁，问：如果该船继续向东航行，有无触礁危险？请说明你的理由.

设函数f（x）=sin²x﹣cos²x﹣4sin（x+ $\frac{\pi }{4}$ ）sin（x﹣ $\frac{\pi }{4}$ ）

如图为定时爆炸装置示意图，虚线框内是其内部电路，a、b为暴露在外面的两根导线 $.$ 拆弹专家要在a、b两根导线中做出正确选择，将其中一根导线剪断即可使起爆器失效；若不慎剪断____ $($ 选填“a”或“b” $)$ 导线，起爆器就会引爆 $.$ 定时装置 $($ 图中未画出 $)$ 相当于一开关，正常处于闭合状态，当到达设定时间时，开关断开，起爆器引爆，则定时装置应串联在____ $($ 选填“CD”或“EF” $)$ 之间．

    Students perform better when their instructors use hand gestures—a simple teaching tool that could generate benefits in higher－level math such as algebra(代数)．

    A study published in Child Development,the top－ranked educational psychology journal,provides some of the strongest evidence yet that gesturing may have a unique effect on learning.Teachers in the United States tend to use gestures less than teachers in other countries.

     "Gesturing can be a very beneficial tool that is completely free and easily employed in classrooms," said Kimberly Fenn,study co－author and assistant professor of psychology at Michigan State University."And I think it can have long－lasting effects."

    Fenn and Ryan Duffy of MSU and Susan Cook of the University of Iowa conducted an experiment with 184 second－,third－ and fourth－graders in Michigan elementary classrooms.

    Half of the students were shown videos of an instructor teaching math problems using only speech.The others were shown videos of the instructor teaching the same problems using both speech and gestures.In the speech－only videos,the instructor simply explains the problem.In the other videos,the instructor uses two hand gestures while speaking,using different hands to refer to the two sides of the equation.Students who learned from the gesture videos performed better on a test given immediately afterward than those who learned from the speech－only video.

    Another test was given 24 hours later,and the gesture students actually showed improvement in their performance while the speech－only students did not.

    While previous research has shown the benefits of gestures in a one－on－one tutoring－style environment,the new study is the first to test the role of gestures in equivalence learning in a regular classroom.

    The study also is the first to show that gestures can help students transfer learning to new contexts—such as transferring the knowledge learned in an addition－based equation to a multiplication－based equation.

    Fenn noted that U.S.students lag behind those in many other Western countries in math and have a particularly hard time mastering equivalence problems in early grades."So if we can help them grasp this foundational knowledge earlier," she said,"it will help them as they learn algebra and higher levels of mathematics."

第二节

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

A garden that's just right for you

     Have you ever visited a garden that seemed just right for you, where the atmosphere of the garden appeared to total more than the sum(总和) of its parts? ____ . But it doesn’t happen by accident. It starts with looking inside yourself and understanding who you are with respect to the natural world and how you approach the gardening process.

●____ 

     Some people maythink that a garden is no more than plants, flowers, patterns and masses of color. Others are concerned about using gardening methods that require less water and fewer fertilizers(肥料). ____ . However, there are a number of other reasons that might explain why you want to garden. One of them comes from our earliest years.

●Recall(回忆)your childhood memories

     Our model of what a garden should be often goes back to childhood. Grandma’s rose garden and Dad’s vegetable garden might be good or bad, but that’s not what’s important. ____--how being in those gardens made us feel. If you’d like to build a powerful bond with your garden, start by taking some time to recall the gardens of your youth. ____ then go outside and work out a plan to translate your childhood memories into your grown-up garden. Have fun.

A. Know why you garden

B. Find a good place for your own garden

C. It's our experience of the garden that matters

D. It's delightful to see so many beautiful flowers

E. Still others may simply enjoy being outdoors and close to plants

F. You can produce that kind of magical quality in your own garden, too

G. For each ofthose gardens, writer down the strongest memory you have