And it can be contracted into a smaller thing.

而且可以收缩成更小的东西。

So, we're using a present perfect form, but we've contracted it into one word, as opposed to two words, and: " They've" .

因此，我们使用的是现在完成时形式， 但我们将其缩减为一个词， 而不是两个词，并且：“他们已经” 。

An astronomical toddler, the host star has the same mass as our sun but twice the radius, meaning it hasn't contracted fully into its final shape yet.

作为一个天文幼儿， 主星的质量与我们的太阳相同， 但半径是太阳的两倍，这意味着它还没有完全收缩成最终形状。