21.   But it takes discipline to become fit, and hard work to remain so.

22.   But many added that much work remains to be done.

23.   But much work remains before such a process could become commercially viable.

24.   But much work remains to be done.

25.   But much work remains.

26.   But scientists said much work remains in filling in the gaps in this first draft of the sequence.

27.   But the street-level economy where most Mexicans live and work remains deeply mired in one of the worst recessions this century.

28.   But theater work remains important to her.

29.   But the street level economy where most Mexicans live and work remains mired in a deep recession.

30.   But with fighter patrols over Eastern cities, much work remained to be done.