A hydrocarbon was known to be either an alkene or alkane.某碳氢化合物已知可能是烯烃或是烷烃.The hydrocarbon must be an alkene.这个碳氢化合物必定是烯烃.The betaine will collapse to the alkene only when these two functions are eclipsed.只有当这两个基团移至重迭位置时...
The woodpecker just looked on coldly, and then flew away contentedly.而在旁边冷眼看着的啄木鸟, 这才满意地飞走了.The woodpecker pecked a hole in the tree.啄木鸟把树啄了一个洞。Hi , Woodpecker, would you like to have a picnic with me?啄木鸟, 你愿意和我一起去野餐 吗 ?...
Huge catfish are skinned and dressed by hand.用手剥去巨鲇的皮,并剖洗干净.The catfish deposits its eggs in shallow water, generally dose to roots or close to reeds.鲇鱼通常在苇根或苇干附近的浅水里产卵.South American catfish having the body covered with...