i'd like two cups of tea for cooking vegetables.哪里错了

i'd like two cups of tea for cooking vegetables.哪里错了

i'd like two cups of tea for cooking vegetables.
for改为when
意思是：我在做菜的时候需要两杯茶.
而不是：我做菜需要两杯茶.（for在这里的意思是：...用来做...)