It is very difficult to _____ the green beans from the red ones, because there are too many of them. [ ]

A. work out

B. watch over

C. set down

D. sort out

小剂量亚甲蓝治疗（）

A.有机磷中毒

B.铅中毒

C.氰化物中毒

D.亚硝酸盐中毒

E.急性酒精中毒