下图表示“探究种子萌发的环境条件”的实验，请分析回答问题(短线上填文字，
内填图中种子编号)。

提出问题：种子萌发需要的外界条件是什么？
作出假设：种子萌发需要充足的空气、适宜的温度和足够的水分。
制订计划：如图。
(1)种子①、②的变量是____ 。
(2)种子②、____ 的变量是充足的空气。
(3)种子⑤、____ 的变量是适宜的温度。
实施计划：种子②萌发了，种子①、③、④、⑤、⑥没有萌发。
得出结论：种子萌发需要____ 、____ 和____ 。

   Let me tell you my pen friend Ivan. He is 12 years old. He likes playing football. He usually play football with his friends at weekends.
Ivan lives with his father and mother in a city in France. They have a dream home with five rooms, a swimming pool and a garden. They often have a party in the garden at weekends. They like to help their neighbours. His home is not near his school, so Ivan takes a bus for an hour and then walks for 10 minutes to school. There is a Basketball Club near his school. He likes play basketball in the club.
   Ivan's father is a worker. He is busy. Ivan's mother is a doctor. She is nice to the patients. Ivan wants to be a teacher when he grows up. I want to be a teacher, too. Every month Ivan writes two letters to me. He'll come to Suqian next year. We'll meet then.