填空题

Researchers in Troy, New York, have made the world’’s smallest brushes, with bristles a thousand times thinner than a human hair. They’’re (36)________to sweep clean the tiny world of nanotechnology. Brushes, brooms and hairy fly swats are probably among the first tools (37)________ by humans. (38)________, an ancient paintbrush used by a prehistoric cave artist (39)________ from 30,000 years ago. So it’’s (40)________ that miniature versions of these should adorn the burgeoning field of nanotechnology. The bristles of these new nanobrushes are made of tiny (41)________ filaments thirty billionths of a meter across and a few (42)________long. The brush handles they’’re attached to are comparatively large — (43)________ than a human hair! The researchers have taken microscope pictures (44)________________________—particles that would escape any normal brush. The researchers also used their brushes to paint microstructures; and (45) ________________________. If the tiny tools prove robust enough, (46)________________________ or sweeping away unwanted crud.