根据提示填空：人们砍树，烧树使温室效应更严重，因为树吸收有害气体。大量砍树也导致洪水，因为树帮助稳固土壤，下雨时土壤吸收水分。
The burning and cutting down of trees is making the greenhouse effect（66）_________because trees take in（67）_________gases．It will also cause（68）_________because trees can help（69）_________soil together，and soil（70）_________water when it rains．