alert, cautious, considerate 辨析

alert, cautious, considerate这一组形容词都表示"小心的，谨慎的"。
alert a.警惕的，留神的。
The hostess remained standing, alert to every guests' drinking need.女主人一直站在旁边，时刻准备给大家斟酒。
cautious a.细心的，谨慎的。
He has a cautious attitude about spending money.在花钱的问题上他态度谨慎。
considerate a.关心他人的，体贴的。
He is always considerate of others; he is kind and sympathetic.他总是很体谅他人，并且慈祥而富有同情心。