植物蒸腾失水的“门户”和气体交换的“窗口”是( )
等腰三角形的腰长为5,一腰上的高为3,则这个等腰三角形底边的长为____
cos-13π3=( )
(____)A. I have two storybooks.
(____)B. It's a maths book.
(____)C. I lost my schoolbag.
(____)D. It's a fat panda.
(____)E. I have three keys in my schoolbag.