illegal（非法的）
1. It is illegal to park here.（在这里停车是非法的。）
2. Illegal activities will be punished by law.（非法活动将受到法律的惩罚。）
3. He was arrested for illegal drug possession.（他因非法持有毒品而被捕。）
illogical（不合逻辑的）
1. His argument is completely illogical.（他的论点完全不合逻辑。）
2. An illogical decision may lead to bad consequences.（一个不合逻辑的决定可能会导致不良后果。）
3. The story has some illogical plot points.（这个故事有一些不合逻辑的情节。）
illegible（难以辨认的）
1. The handwriting on this paper is illegible.（这张纸上的笔迹难以辨认。）
2. The sign was so faded that it became illegible.（这个标志褪色得很厉害，变得难以辨认了。）
3. His notes are often illegible.（他的笔记经常难以辨认。）
illiterate（文盲的；不识字的）
1. In some remote areas, there are still many illiterate people.（在一些偏远地区，仍然有很多文盲。）
2. Being illiterate can limit one's opportunities.（不识字会限制一个人的机会。）
3. She is trying to help illiterate adults learn to read.（她正在努力帮助文盲成年人学习阅读。）
ill-fated（注定不幸的）
1. Their ill-fated relationship ended in tragedy.（他们注定不幸的关系以悲剧告终。）
2. The ill-fated expedition met with many difficulties.（那次注定不幸的探险遇到了很多困难。）
3. His ill-fated attempt to climb the mountain failed.（他注定不幸的登山尝试失败了。）