细胞不需要的物质一定不能通过细胞膜。
— ______ today!
— Yes. Shall we go to the park this afternoon?
光线从空气斜射入水中，若入射角为32°，则折射角为（ ）
It was late. She opened the door ________ because she didn't want to wake up her grandma.
已知三角形的两条边长分别是7和3，第三边长为整数，则这个三角形的周长是偶数的概率是____．
