TheSalkvaccineisamajorfactorinthefighttoeradicatepolio.

By the nineteenth century, embroidery on men's clothing had virtually disappeared except for the occasional decorative vest and tie.

The first paper was made from the bark of the mulberry tree.

Withlasersscientistscanprobemanyphysicalprocesses,suchascombustion,oncebeyondourken.视野

TheeconomyofDallas,Texas,isstronganddiversified.