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1·The selective accretion theory chalks it up to high gas density in the early solar system, during the planet's formation.

选择性附加理论写出它的高气体密度在早期太阳系，在行星的形成。

2·In a one-star system like our solar system, the leading theory as to how the planets formed is through a process called accretion.

在单星系如我们的太阳系中，普遍认定行星是通过吸积的过程逐渐形成的。