这个理论说我们的太阳系有第十颗行星(如果您将冥王星算作第九颗行星的话，否则这颗神秘的行星就是第九颗。)

This theory says that our solar system has a 10th planet (if you count Pluto as a planet, otherwise the mystery planet is no. 9).

youdao

这个理论说我们的太阳系有第十颗行星(如果您将冥王星算作第九颗行星的话，否则这颗神秘的行星就是第九颗。)

This theory says that our solar system has a 10th planet (if you count Pluto as a planet, otherwise the mystery planet is no. 9).

youdao