-tree bbbee be-er beber becue becum becut beebe beete beeut bembe bemer bemet berbe bercu berec beret berme berre berru berte berum betee beter betre bett- bette beuer beure beute brebu brece breem breer breet breme bremm brere brett breu- brmmm brrrr bruce bruer bruet brume brumm brute btc-e btr-t bubbe buber bucet bucum bucur bumbu bumme burcu buret burru burte burtt buruc burut butec buter butme butte butut c-met c-tec ccccc ccett cebec ceber cecum ceere cemec cemre cerbu cerc- cerce cerec cerer ceret cerre certe cetme cette cmere crebe crece creem creer creme crete cretu creu- creue cruce cruet crumb crume crure ctcum ctree cttee cubbe cubeb cuber cubub cumbe cumbu cumec cumm- curce curer curet curre cutcu cutee cuter ebber ebbet ebert ebure ecume eeeee eembc eemct embee ember embue emcee emeer emere emert emmer emmet emtec emtee emure erbbe erber erect erem- erere errtu erte erter eruct etete etree etter eturu eucre eum-u eurre mbcet mbebe mbere mbret mbube mburu mcbee mccue mcree mcube mebbe mecum meece meemu meere meete membe memer merce merer meret merre merte merur meter metr- metre mette metur meuer meure meute mmccc mmmcc mmmmm mrcub mreru mrmet mt-tc mt-te mt-tm mt-tr mt-tt mtree mtume muctc mucum mucur mumbe mumcu mumme mummu muret mureu murre murru murum murut muter mutet mutum rebbe rebec reber rebet rebut recce recet rect- recte recue recur recut reece reeme reere remee remer remet remue rere- reree reret rerum retee retem reter rette reuer reuet reume reute rmutt rubee ruber rucer ruere ruete rumbe rumer rummu rurec ruter rutte ruutu tbtbt tbutt teber tebet tectb tecum teeme teemu tembe tembu terce terem teret tereu terme terre tert- teter tetr- tette treer treet treme trere trete trett treut trubu truce truer trume trute ttttt tuber tucet tuctu tucum tumbe tumbu tumut turbe turbt turem turet turre turtu turut tutee tutte tuuru u-cee uber- ubume umbe- umber umbre umeer umeme ureme urter urubu uruce urucu urutu uter- utmer utrum utter uttur utube uturu uuuuu