【2014－03-20 the first day in spring】
看來老美是以春分為 春天的第一天
spring equinox 春分 在中國是 農曆二月廿1日（明天） 2014－3－21
The season officially begins at 12:57 p.m. ET on March 20 —
a precise and fixed point in time defined as
when the center of the sun passes directly over the Equator.
(See "Vernal Equinox Pictures: First-Day-of-Spring Celebrations.")
But biological signs of spring's arrival are a different science, defined
by the timing of events—such as the first appearance of flowers —
that change from year to year and place to place.
