能准确滴定金属离子的条件是（Et<= 0.1%） （ ）
A. KMY≥106
B. K/MY≥106
C. cKMY≥106
D. cK/MY≥106
在配位滴定中，须使溶液的酸度比测定该离子所允许的最高酸度要高。（ ）
A. 对
B. 错
Why does Bob stand by the doorway in Scene 1?
A. He is looking for a criminal.
B.It is the doorway to his home.
C.He is waiting for his old friend.
D.He is a police officer and is just checking the area.
Why does Miles hide his face in Scene 2?
A. He is scared of Bob.
B.He has a terrible facial injury.
C.He wants Bob to think he is Jimmy.
D.He knows Bob would be scared of him.
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