21.   Actually, there were several large samples and it was incumbent upon me to try them.

22.   But this meant destroying a large sample to get the five grams of carbon necessary for the test.

23.   By contrast, he said the chip can analyze a few drops of protein, eliminating the need to grow large samples.

24.   Earlier methods required large uncontaminated samples, but these were impossible to get because of damage from original conservation methods.

25.   However, getting results takes a long time and the lab needs a relatively large sample -- at least a dime-sized smear of blood on a cloth.

26.   However, the work in the military has relied on comparatively large samples that provide ample material for analysis, Wraxall said.

27.   In their modest apartment, Mr. and Mrs. Khojaev recently showed a visitor large samples of their collection, which few outsiders have seen.

28.   Previous methods of carbon-based dating required that a large sample of the material be analyzed.

29.   Tape the large sample up on your wall and study it at various times over several days under natural and artificial light.

30.   The PCR is inexpensive and does not require a large sample of material, but has been inconclusive in many cases.