题目

—It was really tiring for me to stand in the queue for two hours to get the G- train ticket. —You ____. You could have got one online. A . needn't B . needn't have C . didn't need to D . didn't need to have 答案：B下列关于光合作用的叙述中，正确的是                                                                   （    ）       A．尽量提高空气中的C02浓度，光合作用速率也能随之大幅度提高       B．光合作用必须有光照，但光照过强可能降低植物的光合速率       C．在暗反应中，ATP可以提供能量，有还原作用并能供能的物质是NADP+       D．能吸收、传递、转化光能的只有少数特殊状态下的叶绿素a