Using technology as new as space-age fabrics and as ordinary as common dry-cleaning chemicals, scientists and historians, in their attempt at cleaning and preserving the American flag that flew over Fort McHenry in Baltimore in 1814, are hoping that it will then last another 200 years.
(A) and as ordinary as common dry-cleaning chemicals, scientists and historians, in their attempt at cleaning and preserving the American flag that flew over Fort McHenry in Baltimore in 1814, are hoping (B) and as ordinary as common dry-cleaning chemicals, scientists and historians are attempting to clean and preserve the American flag that flew over Fort McHenry in Baltimore in 1814, hoping
