Sprite and FlexSprite are the base classes that don't require a time line, and you can extend these to write your own custom classes.

Sprite和FlexSprite是不需要时间线的基类，您可以通过扩展它们编写定制类。

youdao

"If you have moved house, you know how much time is wasted constructing the base of the box before you can put anything in it, and it's even worse on a factory assembly line," he says.

“如果你曾经搬过家，你就会知道在装东西之前把盒子撑起来是件多花时间的事情，在工厂的装配线上问题更加严重，”他说。

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Greenwich thus became established as the location of the prime meridian of longitude, and the base line for calculating time zones around the world.

由此格林威治不仅作为起初子午线的所在地，也成为全球计算时区的基准线。

youdao

Mr. JOHN GRAHAM (Smithsonian Air and Space Museum): And we're on a very tight time line, and the reason for that is we need to get to the base of the next hill to the south, which has got north-facing slopes, so that we can get up and basically repeat what we did last winter on Husband Hill: turn the solar panels towards the sun and survive.

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