keen、acute、sharp与shrewd这些形容词均有“锐利的、敏锐的、机敏的”之意。
keen : 多指对复杂艰深的事物或问题有敏锐的观察和敏捷的理解。
- a keen sense of smell
灵敏的嗅觉
acute : 侧重感觉敏锐，能分辨出一般人难以觉察的细微区别。
- acute eyesight/hearing
敏锐的视觉／听觉 - an acute sense of smell
灵敏的嗅觉 - a woman of acute intelligence/judgment
机敏聪颖／有敏锐判断力的女性
sharp : 指人头脑精明、敏锐或机警。
- Birdwatchers need to have sharp ears and eyes.
观鸟者必须有敏锐的耳朵和眼睛。 - She has a sharp eye for a bargain.
她非常善于发现便宜货。 - Our new director is very sharp.
我们的新主任非常精明。
shrewd : 指有头脑，善于判断分析，精明过人。
- He was shrewd enough not to take the job when there was the possibility of getting a better one a few months later.
他很聪明没有接受那份工作，因为几个月后他有可能会得到更好的工作。 - She is a shrewd politician who wants to avoid offending the electorate unnecessarily.
她是一个精明的政治家，想避免不必要地得罪选民。
（拓展学习： 小词详解 | shrewd）
