密度越小,土壤越板结。
参考答案:错
--- Does Susan like singing?
--- Yes, she does. But she prefers __________ to _________.
A.to dance; sing
B.to dance; singing
C.dancing; sing
D.dancing; singing
有氯化钠溶液、氢氧化钠溶液、硫酸、水、盐酸五瓶液体,给你以下药品,请你从中选择合适的物质,用尽量简便的方法把它们一一鉴别出来,并完成实验报告.
供选择的药品:氯化钡溶液、锌粒、酚酞溶液、石蕊溶液、碳酸钠溶液、澄清石灰水、硝酸银溶液.
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