词根词缀：bi-, bin-, bino-, bis-
【来源及含义】Latin: two, twice, double, twofold; a number; it normally functions as a prefix
【相关描述】This bi- is used before s, c, or a vowel. Don't confuse this bi- with another one which means "life".
All words except biennial referring to periods of time and prefixed by bi- are potentially ambiguous. Since bi- can be taken to mean either "twice each" or "every two", a word like "biweekly" can be understood as "twice each week" or "every two weeks".
【同源单词】biacid, biangular, biannual, biannual, biarchy, biarticulate
词根词缀：ped-, pedi-, -pedal, -ped, -pede, -pedia
【来源及含义】Latin: foot, feet; people often see this ped element in other words. When people refer to "pedal extremities", they mean "feet". When anyone pushes the pedals of a bicycle, it is done with the feet. A pedestrian must use the feet for walking. A quadruped has four feet while a centipede has "100 feet"; or a large number of them because it may be impossible to count all of them.
【相关词根词缀】 Related "foot, feet" units: melo-; planta-; podo-; -pus.