海滩上，蚂蚁为了获取潮汐遗留下来的食物，有时居然也会游泳，这一现象体现了( 　 )

根据短文内容，选择正确答案。
   It’s Sunday morning．There are many people in the park，some boys  are playing basketball．There are some girls under a big tree．They’re singing and dancing．What are those women doing? They are drinking tea．Look at the woman in a blue coat．Who's she? She’s my mother．She is talking to Lin Feng．Lin Feng is her student．He is a good student．He studies hard．He’s good at all the subjects． And he's friendly to all his teachers and his friends．

— Let's join the English club.       

— ________.