问题
选择题
We are not allowed in public.[ ]
A. to wait in line
B. to pick up the litter
C. to smoke
D. to keep your voice down
答案
答案：C
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We are not allowed in public.[ ]
A. to wait in line
B. to pick up the litter
C. to smoke
D. to keep your voice down
答案：C
且E为日常生活中常见金属，其余均 为化合物
。它们之间的转化关系如图所示(反应中生成的水及次要产物均已略去)。