Burnscanbecausedbyavarietyofthings,anddependingonwhich..中的depend为什么用ing形式
Burnscanbecausedbyavarietyofthings,anddependingonwhichlayersoftheskinareburned,burnscanbedividedintofirst,secondandthirddegreeburns.中的depend为什么用ing形式