题目

-Your spoken English is very good. - _________ . A. The same to you B. That's all right C. You are right D. Thank you   答案：D如果不断地增加二氧化碳的浓度，则光合作用强度的变化情况是A.增强→减弱→不变B.增强→不变→不变C.不变→减弱→增强D.减弱→不变→增强