we must t____to exercise every day.

we must t____to exercise every day. People must be really t____to you for your work We do morning exer in the morning 中的in可以改成on么? We must 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 “we must study them.是“we must study them. we must keep our classroom( ). we must ( ) our school nuiforms ( we must start tomorrow morning. We must ___(be) careful.