题目

—If the traffic ________ busy, Linda won't catch the train in one hour.—I know. I will call her to leave for the train station at once. A . is B . will be C . was D . has been 答案：A下列有关生态系统功能的叙述，不正确的是（　　）A．生态系统的能量流动是指生态系统内伴随物质循环的能量转移的过程B．能量流动和物质循环可以长时期地保持动态平衡C．食物链可以无限地延伸下去D．生态系统中的能量最终以热能形式散失到环境中