问题 问答题 简答题

从养分循环特点上比较自然生态系统和农业生态系统。

答案

参考答案:

农业生态系统形成了不同于原有自然生态系统的养分循环特点:

一是农业生态系统有较高的养分输出率与输入率。

二是农业生态系统内部养分的库存量较低,但流量大,周转快。

三是农业生态系统的养分保持能力较弱,流失率较高。四是农业生态系统养分供求同步机制较弱。

解答题
改错题

短文改错

       此题要求改正所给短文中的错误。对标有题号的每一行作出判断:如无错误,在该行下边横线上画一个勾;如有错误(每行只有一个错误),则按下列情况改正:

        此行多一个词:把多余的词用斜线(\)划掉,在该行下边横线上写出该词,并也用斜线划掉。

        此行缺一个词:在缺词处加一个漏字符号,在该行下边横线上写出该加的词。

        此行错一个词:在错的词下划一横线,在该行下边横线上写出改正后的词。

        注意:原行没有错的不要改。

     An old friends of mine from Beijing telephoned from                      1.________

the airport to tell me that he has arrived. I was still at the                     2.________

office at that time. I told him which my house was and that                  3.________

I had left the key under the doormat. I asked for him to                      4.________

make him at home. Two hours later, I telephoned him.                        5.________

He told me he couldn't find the key under the doormat, and                6.________

he  had no difficulty in entered my house, because the                         7.________

window of my living room was just by the apple tree, and                   8.________

he had climbed in. I was surprised. There has no                                9.________

apple tree in front of my living room, but there is

one on front of my neighbour's.                                                          10.________