It was the truth that the black reached a stage_______ they had almost no rights at all in the past.   

A．when

B．where

C．which

D．that

预防胱氨酸结石可服用（）

A.氧化镁或维生素B₆

B.氯化铵

C.碳酸氢钠和别嘌呤醇

D.卡托普利

E.碱性枸橼酸盐