英语语法分析

Other ancient civilisations certainly knew about kites; as early as 1250 BC, the Chinese were using them to deliver messages and dump flaming debris on their foes.

其他古代文明当然也了解风筝的用途；早在公元前1250年，中国人就用它们传递信息，向敌人投掷燃烧的碎片。

Travel, except during the Dark Ages, has continued to grow and, throughout recorded history, has played a vital role in the development of civilisations and their economies.

除了在黑暗时代之外，旅游业一直在持续发展壮大，并且贯穿有记录以来的历史，始终在各文明及其经济的发展中扮演着至关重要的角色。

Since the lifetime of a planet like ours is several billion years, we can expect that, if other civilisations do survive in our galaxy, their ages will range from zero to several billion years.

由于我们这样的行星的寿命是几十亿年，我们可以预测，如果我们星系中有其他生物生存，它们的年龄将从零到几十亿岁不等。