将两株植物放在封闭的玻璃罩内，置于室外并用全素营养液进行培养（如图甲所示），假设玻璃罩内植物的生理状态和自然环境中相同，且空气温度对植物蒸腾作用的影响、微生物对CO₂浓度的影响均忽略不计。现用CO₂浓度测定仪测定了一天中该玻璃罩内CO₂浓度的变化情况，绘制成乙图所示曲线。请据图分析，下列说法正确的是（ ）

751年，安西节度使高仙芝所率唐军与阿拉伯军队在怛罗斯发生大战，激战五日后，唐军败北，被俘的中国士兵中有会造纸术的，……不久，阿拉伯帝国范围内的巴格达、开罗等地都陆续出现了一批造纸工场。对这段材料理解正确的是（   ）

    Do you know about Xiong'an? It's a new city near Baoding. There is a big lake in Xiong'an. Yes, it is Baiyangdian Lake. It is very big. In summer, you will see many beautiful lotus flowers on the lake. Some are red. Some are pink. Many people like them. There will be many boats on the lake. And there will be many birds singing in the grass. Xiong'an is beautiful and new. You can come here by bus from Baoding. And you can come here by train. You will play in the water with your friends. You will eat delicious fish. You will take many wonderful pictures. You will have a nice trip in Xiong'an.