particle: implies an amount of a substance or quality that is within the range of visual or mental perception: a rumor without a ~ of truth.


bit: suggests the least feasible amount, extent, or degree: a movie that was a ~ too violent.   feasible可行的，可以在现实中出现的


mite: may stress either smallness in size or minuteness in amount: doesn't have a ~ of suspicion.    （minute极小的implies extreme smallness，如a beverage with only a minute amount of caffeine饮料中只有极少量咖啡因）


smidgen: may go even further in stressing minuteness or scarcity: left them without even a ~ of hope.   （scarce缺乏implies a falling short of a standard or required abundance，如jobs were scarce during the Depression大萧条时工作缺乏，如food was scarce and expensive食物缺乏，价格昂贵）


whit: used chiefly in negative phrases, implies the least conceivable amount: cared not a ~ about their opinion.  


atom: suggests the very smallest size or amount possible: not an ~ of dust escaped his attention.


iota, jot: are used interchangeably to mean the smallest or most minute detail or amount: tried to remove the last ~ of doubt; added not a ~ to their knowledge.


tittle: has the same meaning as iota and jot but is usually used in the phrase jot or tittle: didn't care a ~ about the opinions of others.


particle微粒颗粒: 表示物质的数量或特征在视觉或思维的感知范围内，bit一点: 表示现实中最小的数量范围程度，mite一点螨虫: 强调尺寸小或数量少，smidgen一点: 进一步强调尺寸小或数量少，whit一点: 指能设想的最小数量，用在否定句，atom一点原子: 表示可能的最小尺寸数量，iota,jot一点: 可互换表示最小的细节或数量，tittle一点: 意思相同，用于词组jot or tittle


记忆方法: 1）首字母PBMSWAIJT重组成WAIT JP MBS等待日本没本事<==微粒     "微"是会意字，从彳(chì)--(wēi)声，本义是"隐秘地行走"，如微行微服微词(隐晦的批评)；引申为"细小"，如细微微量微乎其微微调忽微；另外和物理量连用时表示"百万分之一"，如微米微克         "粒"本义是"米粒谷粒"，其中"米"指谷籽，"立"指独立，合起来表示"煮食时仍可分出独立谷籽的主食"，与"面"相对，面表示"谷粉"       "小"的字形像三颗细碎的粒状物，是"少"和"沙"字的初文。本义为"细碎的沙尘微粒"，最早有3个意思，1、数量上表示"数量不多"；2、质地上表示"沙粒"；3、形体上表示"微粒"，后来小字专表此义。引申指"微小"，与"大"相对。另外2义后来用"少"和"沙"表示
                  2）微粒的意思是很小一块mean a very small or insignificant piece or part.