fathom

n. 英寸（量水深，等于1.8米）v. 彻底明白，了解

fat, fat cat, fat-head, fatal, fatalism, fatalist, fatalistic, fatality, fatally, fate, fateful, fatefully, father, Father Christmas, Father Time, father-figure, father-in-law, fatherhood, fatherland, fatherly, fathomless, fatigue, fatiguing, fatness, fats, fatstock, fatted, fatten, fattish, fatty, fatuity, fatuous, fatuously, fatuousness, faucet, fault, faulted, faultfinder, faultfinding, faultily,