The formation of the channel is initiated when electrons surgefrom the cloud base toward the ground.
当电子从云层底部涌向地面时，通道就开始形成了。
2
Meanwhile the mobile phone subscriptions in developing countries have witnessed a slow increase from 1990 to 2004 and then a great surgefrom 2004 to 2007: the biggest surge happens from 2005 to 2006.