选择题：维生素

119. I was giving a talk to a large group of people，the same talk I ___to half a

112. With his work completed, the manager stepped back to his seat, feeling plea

[填空题,2分] 双子叶植物的保卫细胞呈________________形。

高等植物

[填空题,2分] 被子植物的种子依据胚乳的有无，分为_____和无胚乳种子两种类型。