①围湖造田 ②排放污水 ③植树造林
④焚烧垃圾 ⑤养花种草 ⑥喷药灭虫
_____ his surprise, Peter's teammates all nodded ______ agreement.
如图,∠DAE=∠ADE=15°,DE∥AB,DF⊥AB.若AE=10,则DF等于( )