题干
— Sammy, do you like the grammar book?
—Oh, I love it very much because it is so practical.
A：interesting
B：perfect
C：useful
答案(点此获取答案解析）
C
— Sammy, do you like the grammar book?
—Oh, I love it very much because it is so practical.
A：interesting
B：perfect
C：useful
有Al3+和NO3-，检验此溶液中是否大量存在以下6种离子；①ClO-②NH4+③Fe2+④K+ ⑤HCO3-⑥Cl-，其中不必检验就能加以否定的离子是（ ）
