题目

请将下列“果实与种子的形成”的概念图补充完整：  ①              ②           ③          ④            答案：①卵细胞    ②胚     ③ 子房壁     ④果实— ___________does your sister walk her dog?— Once a day．A．How many B．How fastC．How soon D．How often