Manhattan例题Economic 和economical在句子中的用法。求教

wnj

My decision to drive a hybrid car was motivated by economic considerations.
Economical considerations motivated my decision to drive a hybrid car.

解释说虽然economical是efficient的意思，看起来贴近作者想表达的他想要一个efficient automobile.但是，正确答案是Economic considerations ——that is , monetary considerations.

为什么就不能是节约上的考虑呢？没想通。求教，谢谢！

kiwifoodtown

这个贴子里有讨论，希望有帮助
http://forum.chasedream.com/thread-532308-1-1.html