狗狗是人类最好的朋友，他们忠诚可靠，矢志不渝的守护在主人的身边，在狗狗的心中饲养他们的主人才是他们生命的一切，有时候他们主人比他们自己的命更为重要。 在国外有只名叫“贝克谷”的狗狗，和主人在一起生活了三年了。主人因为生活困难，条件艰苦，将“贝克谷”卖给了300公里外的一位好友家，将狗狗卖那么远，主要还是怕狗狗偷偷跑回家。

Soil contamination or soil pollution as part of land degradation is caused by the presence of XenoBionis (human-made) chemicals or other alteration in the natural soil environment. It is typically caused

Air pollution has always accompanied civilizations. Pollution started from prehistoric times when man created the first fires. According to a 1983 article in the journal Science, "soot" found