动词不定式和动名词做表语区分

问题描述:

动词不定式和动名词做表语区分
his wish is to be a astronaut.(为什么用动词不定式?用is being不可以吗?)
his hobby is play basketball.(为什么要用动名词?用to play )

用不定式表示将来,说到wish那应该用将来
his hobby is playing basketball
用动名词表示一种恒常的状态
就是说喜欢打篮球是一直喜欢的,不是变来变去的那种