The subnet mask is an octet that USES the number 255 to represent the network address portion of the IP address and a zero to identify the host portion of the address.

子网掩码由四个字节组成，它的值为255时表示IP地址中网络地址的部分，值为0时则识别IP地址中表示主机号的部分。

youdao

Wearing hard-hat, paper mask, and gloves I walked around Ground Zero with ministry students giving bottles of water, Red Bull, and chewing gum to first-responders working the pile.

FORBES: If You Don't Take Time To Remember, You Forget