天然气灶烧水,燃烧0.5m3的天然气,使100kg的水从20℃升高到70℃.已知水的比热容为C=4.2×103J/(kg•℃),天然气的热值为q=7.0×107J/m3.求:
生态系统的正常运转与其功能密切相关,生态系统的功能不包括( )
一I think I've got a bad cold,Doctor.Shall I take some medicine?
一No need.Your body itself is able to the virus. Just drink more water and rest.
Most of my friends, _________ Sandy, Jimmy and Angela,are all kind to me.