bug 指小昆虫，尤指吸血的臭虫，也可指细菌。
insect 含义广泛，多指蚂蚁、黄蜂、蝉等等。
pest 指有害的昆虫或有害的小动物。
worm 侧重指蚯蚓、蚕、毛虫等小而无骨的虫。
参考例句
1. She suspected the phone had been bugged. 她怀疑她的电话已被窃听了。
2. A big black bug bit the back of a big black bear. 一只大黑臭虫在一只大黑熊的背上咬了一口。
3. You must specify a component for your bug report. 必须在错误报告中指定一种元件。
英英解释
n.
1. general term for any insect or similar creeping or crawling invertebrate
2. a fault or defect in a system or machine
3. a small hidden microphone; for listening secretly
4. insects with sucking mouthparts and forewings thickened and leathery at the base; usually show incom
5. a minute life form (especially a disease-causing bacterium); the term is not in technical use v.
1. annoy persistently
2. tap a telephone or telegraph wire to get information
