问题 问答题 简答题

举例说明非侵染性病害发生特点是什么?

答案

参考答案:

非生物因素导致的病害称为非传染性病害,这些病害不能传染。从病植物上看不到任何病征。往往大面积同时发生同一症状的病害;没有逐步传染扩散的现象等。如缺素症,高温引起的灼伤。

单项选择题
单项选择题

在Cisco路由器上建立一个名为zw246的DHCP地址池,地址池的IP地址是176.115.246.0/24,其中不用于动态分配的地址有176.115.246.2~176.115.246.10,缺省网关为176.115.246.1,域名为tj.edu.cn,域名服务器地址为176.115.129.26,地址租用时间设定为6小时30分钟。下列DHCP地址池的配置,正确的是()。

A.Router(config)#ip dhcp pool zw246
Router(dhcp-config)#ip dhcp excluded-address
176.115.246.2 176.115.246.10
Router(dhcp-config)#network 176.115.246.0
255.255.255.0
Router(dhcp-config)#defauh-router 176.115.246.1
Router(dhcp-config)#domain-name tj.edu.cn
Router(dhcp-config)#dns server address 176.115.129.26
Router(dhcp-config)#lease 0 6 30

B.Router(config)#ip dhcp excluded-address 176.115.246.2-10
Router(config)#ip dhcp pool zw246
Router(dhcp-config)#network 176.115.246.0
255.255.255.0
Router(dhcp-config)#default-router 176.115.246.1
Router(dhcp-config)#domain-name tj.edu.cn
Router(dhcp-config)#dns-server address 176.115.129.26
Router(dhcp-config)#lease 0 6 30

C.Router(config)#ip dhcp excluded-address 176.115.246.2 176.115.246.10
Router(config)#ip dhcp pool zw246
Router(dhcp-eonfig)#network 176.115.246.0
255.255.255.0
Router(dhcp-config)#default-router 176.115.246.1
Router(dhcp-config)#domain-name tj.edu.cn
Router(dhcp-config)#dns-server address 176.115.129.26
Router(dhcp-config)#lease 0 6 30

D.Router(config)#ip dhcp excluded-address 176.115.246.2 176.115.246.10
Router(config)#ip dhcp pool zw246
Router(dhcp-conlig)#network 176.115.246.0
255.255.255.0
Router(dhcp-config)#default-router 176.115.246.1
Router(dhcp-config)#domain-name tj.edu.cn
Router(dhcp-config)#dns-server address 176.115.129.26
Router(dhcp-config)#lease 30 6 0