Bythenineteenthcentury,embroideryonmen'sclothinghadvirtuallydisappearedexceptfortheoccasionaldecorativevestandtie.

The Salk vaccine is a major factor in the fight to eradicate polio.

Themegaphone(microphone)makesthevoicesoundlouderbecauseitpointssoundwavesinonedirectionandkeepsthemfromspreadingoutinalldirections.

In the northeastern United States, it rains intermittently 间歇地 throughout the spring.

The company issues an annual report every March.