illusion意为“错觉，幻想，错误的认识”或对实际不存在的事物的“幻觉，幻影”。delusion意为“欺骗，迷惑，幻想，误解”。作“幻想”解时，特指可能为某种癫狂病患者的症状、妄想。有时两者可以换用。
- Cast illusions, prepare for struggle.
丢掉幻想，准备斗争。 - You're under the illusion/delusion that you're always right.
你误以为你总是对的。 - We shouldn't cherish/foster any fond illusions/delusions about anything.
我们对任何事情都不应抱有任何不切实际的幻想。 - Quite a number of people were under a delusion in this matter.
许多人在这件事上受了骗。
拓展学习：
