Cook and his crew would observe Venus gliding across the face of the Sun, and by doing so measure the size of the solar system.

库克和他的船员们将观测金星从太阳上滑过，以此来测算太阳系的大小。

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Because a roof has limited space for solar panels, so you either settle for a smaller system or get the size you want by using solar panels that can produce more power.

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