ill-defined

为了记住“ill-defined”，可以将它分解为“ill”和“defined”两部分。首先，记住“ill”通常与“bad”或“not good”相关联。接着，想象一个形状或者概念因为某种原因（比如“ill”的负面含义）而显得不清晰或者定义不明确。这样，“ill-defined”就关联到了一个不清晰或不明确的事物或概念。

1. "I'm afraid he's ill." — "I'm sorry to hear that."

“恐怕他生病了。”——“真是遗憾。”

2. Her daughters visited him from time to time when he was ill.

他生病的时候她的女儿们时常去探望他。

3. She was so ill that she was put on a respirator.

她病得很严重，被戴上了人工呼吸器。

4. An employer can demand written certification that the relative is really ill.

雇主可以要求出具书面证明，证实员工的亲人确实病了。

5. These various complaints are part of a continuum of ill-health.

这些各种各样的疾病、不适都是身体健康状况欠佳的一种表现。