根据句意及首字母提示完成单词。

当低倍镜换为高倍镜后

《九章算术》是我国古代内容极为丰富的数学名著，书中提到了一种名为“刍甍”的五面体（如图）：面ABCD为矩形，棱EF∥AB．若此几何体中，AB=4，EF=2，△ADE和△BCF都是边长为2的等边三角形，则此几何体的表面积为（   ）

阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项。
A
Live Music—-Late Night Jazz
    Enjoy real American jazz from Herbie Davis, the famous trumpet(号手). He is known to play well into the early hours, so don't want to get much sleep.

PLACE: The Jazz Club     DATES: 15—-23 June PRICE: ￥100-150        TIME: 10 p.m. till late!   TEL: 4668736

Scottish Dancing
    Scottish dancing is nice and easy to learn. The wonderful dance from England will be given.

PLACE: Jack Stein's      DATES: 10-20 May PRICE: ￥150           TIME: 7-10 p.m.  TEL: 4021877

Shows—-Anhui Museum
    There are 12,000 pieces on show here. You can see the whole of Chinese history.

PLACE: Anhui Museum    DATES: 1Mar-30 Jun PRICE: ￥130            TIME: Mon-Fri 9 a.m-5 p.m.   Saturday 9 a.m.-9 p.m. TEL: 4886888

    Your pen friend is coming from Australia to your city for a holiday. You send him this E-mail to tell him something about the hotels.

SUN HOTEL Dates                Prices(a night) 1Oct-31Dec             ￥168 1Jan-31Mar             ￥148 1Apr-30Apr(closed)       …… 1May-31May            ￥188 1Jun-30Sep              ￥208 TEL: 4686788   E-mail: Li Hong@163.com.

ROSE HOTEL Prices(a night) ￥198 ￥178 …… ￥218 ￥248

为了探测海底某处的深度，向海底垂直发射超声波，经过4s收到回波信号，海洋中该处深度是多少米？（声音在海水中传播速度是1500m/s） 科学家发现这种方法是不能用来测量月亮与地球的距离的，其原因是什么？