它意味着外生的铀进入到沙岩中.It includes epigenetic uranium impregnations in sandstone.当TS2成立时我们说解释变量是严格外生的.When TS 2 holds we say the explanatory variables are strictly exogenous....

“外生的”的英语可以翻译为：exogenous，[医] exogenetic，exogenic，ectogenic，ectogenous ...