大多数天线被制成碟形，用以收集和反射无线电波至亚反射器，就像曲面镜将可见光聚焦于一点一样。

Most antennas are made in the shape of a dish to collect and reflect the radio waves to the sub reflector, in the same way as a curved mirror focuses visible light to one point.

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由于你建立了一个数据验证点并选择了可见文本测试，显示的文本是一种文本框的形式。

Because you created a data verification point and choose the Visible text test, the text displays in a text box format.

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对包含该书的表格单元使用可见文本选项来记录数据验证点。

Record a data verification point using the Visible Text option for the table cell containing the book.

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it's clear that you want to add a vector that looks like that, because then you go from the start of this to the finish of that, you end up at the same point and you get this invisible 0 vector.

显然应该给它加上这样一个矢量,因为从这个矢量的起点指向那个矢量的终点,最终指向的是同一个点,你就得到这个不可见的零矢量

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