一般来说,主动语态变被动语态时,主动语态里的主语要变成被动语态里的介词宾语(被...by...),主动语态里的宾语则往往变成被动语态里的主语:
He is making some cakes.----Some cakes are being made by him.
因此,硬要将I play basketball变成被语态的话,应是Basket is played by me.在实际用法上通常是不这么说的.
如果要表达是被自已促使或他人促使去打篮球,可以借助于动词MAKE,FORCE等.如:I was forced to play basketball.
The kite is flying.描述的是风筝在说话时的动作或状态,并不关注是被谁放上去的.fly既可用作不及物动词,也可用作及物动词.用作及物动词时,有make...fly的意思,即"放飞...",因此,放风筝说成fly a kite.风筝在天上飞则是The kite is flying in the sky.