题目

在正常条件下进行光合作用的某植物，当突然改变某条件后，即可发现其叶肉细胞内五碳化合物的含量上升，则改变的条件是 A．停止光照                     B．停止光照并降低二氧化碳的浓度 C．升高二氧化碳的浓度           D．降低二氧化碳的浓度 答案：D_____ to get there within ten minutes. Ten minutes______ too short for us.A. It is impossible for us; are B. It's impossible for us; is C. We are impossible; are D. We aren't possible; is