we must __polluted water__ entering the clean river.prevented,from 和keep ,from选那一个呀?

we must __polluted water__ entering the clean river.prevented,from 和keep ,from选那一个呀? we must protect ourselves （w） We must we must walk to the village .there is no other w( )of going there the lights have three (c ).we must (w )(f )the lights turns (g ) when we need to cross the road . We must face the fact __________ our time is limited and we must cherish every minute.A.which B.on which C.that D.why w.w.w.k.s.5.u.c.o.m When the fire d----- is high,we must be careful.We must not have c--- in the countryside.We must put our rubbish bin.At home ,we must not cook w--- an adult,We must not play near a fire ,It's everyone‘s job not to s----- a fire.首字母填空 We must value what we We must ( )(work)hard. we must call the We must help them? we must help it why we must sleep We must learn it we must find a We must purify the Summer vacation is coming.We will visit World.I think it's interting.You must enjoy yourself.We w翻译一下好么 “we must study them.是“we must study them.