1.The bag costs me 15 yuan.
同义句:
It costs me 15 yuans on the bag.
I spend 15 yuan on the bag
I pay 15 yuan for the bag.
I buy the bag at 15 yuan.
2.I spend 1 hour on my homework every day.
同义句:
It takes me 1 hour to finish my homework every day.
It costs me 1 hour on my homework every day.
I expend 1 hour on my homework every day.