第19题: [单项选择]配制复方碘溶液的正确操作是() A. 先将碘化钾配制溶液,再加入碘使溶解,然后加水稀释至刻度 B. 先将碘加入适量水中,然后加入碘化钾使形成复盐进行助溶,最后加水定容至刻度 C. 先将碘和碘化钾充分混匀,然后加入适量水使形成复盐,最后加水定容至刻度 D. 先分别将碘和碘化钾各加入适量水溶解,然后混匀,最后加入水定容至刻度 参考答案:A
第35题: [单项选择]What are the "unusual traits or situations" referred to in the first sentence A. Patterns of animal and plant growth. B. Food and food preparation patterns of the upland Tibetans. C. Social and familial organization of typical Tibetan society. D. All of the above. 参考答案:D 答案解析:第三段中“the Tibetan uplands had a dry,continental climate with vegetation and animal life similar to…”表