单项选择题双子叶植物的周皮上皮孔是气体唯一的进出通道。
单项选择题根据句义填入合适的词 When the children blew out with a puff, the seeds of the dandelions（蒲公英） ___________ away as if they had wings. A、boasted B、fluttered C、floated D、boosted
