生态平衡
参考答案:
生态平衡指在一定时期和一定范围内,生产者、消费者和分解者之间保持着一种动态的平衡状态,也就是系统的能量流动和物质循环较长时间保持稳定状态。
按要求改写下列句子。
1. I want to have a good talk with Jenny.( 就画线部分提问)
_____ do _____ want to have a good talk with?
2. You speak English very well.( 就画线部分提问)
_____ _____ you speak English?
3. It's nine o'clock now.( 就画线部分提问)
_____ _____ is it now?
4. I phone my friend once a week.( 就画线部分提问)
_____ _____ do you phone your friend?
5. I'm Wang Mei .( 改为电话用语)
_____ _____ Wang Mei _____.
6. John often talks with me.( 用tomorrow 改写句子)
John _____ _____ with me tomorrow.
工业中常见的电化学腐蚀有()。
A、高温硫化
B、渗碳
C、缝隙腐蚀
D、孔蚀