21.   But a new theoretical framework for quasicrystals promises to simplify matters.

22.   But by proving they could be created in great atom smashers, Perl produced experimental evidence to support the theoretical framework of the Big Bang.

23.   Rather, the arguments fit into a larger theoretical framework, the work of a group of scientists who have ushered Darwin into new and provocative areas.

24.   Without a theoretical framework in which they can be arranged, the data are meaningless.