-tree eeeee ef-tu efere efetf effer effet efter efuru efutu ekker ekuku ekuru erere errtu erte erter eruke eteke etete etree etrek etter eturu eurre feere feret ferr- ferre ferte feter fette feuer feute freek freer freet freke frere frett freur frute ftrtt fu-fu futur k-ute keefe keere kefee kerek keret kerre kertu ketek keter kette kreef kreek kreke krete kreuk kruft kukur kurek kurku kurre kurte kuruk kutte kuttu kutur reefe reeft reere refer refet reffe refut rekke rere- reree reret retee reter rette reuer reuet reute rt-rk ruere ruete ruffe rukke ruter rutte ruutu tefe teket tekke terek teret tereu terre tert- teter tetr- tette treer treet trefe treff trere trete trett treut truer truff truke trute ttttt tuffe tufte tukur turek turet turku turre turtu turut tutee tutku tutte tuuru ufere ukeke ukert urker urkut urter urutu uter- utter uttur uturu uuuuu