肝性脑病合并碱中毒时应选用（）
A.谷氨酸
B.精氨酸
C.鸟氨酸
D.色氨酸
E.半胱氨酸
参考答案：B
They became friends again that day. Until then, they _____ to each other for nearly two years. [ ]
A. didn't speak
B. hadn't spoken
C. haven' t spoken
D. haven' t been speaking
