使用不同授权电脑对某台ipad同步，不会删除其他授权电脑对这台电脑同步时所安装的数据
参考答案：错
We went to the West Lake yesterday, _______, not surprisingly, was crowded with visitors from all
over the world. [ ]
A. where
B. which
C. that
D. when
向BaCl2溶液中滴加H2SO4溶液，直到沉淀完全为止．其结果是生成溶液的质量恰好等于原BaCl2溶液的质量，则滴入的硫酸溶液中溶质的质量分数为______．
