And that's probably because that's when everybody got aware of the environment and Earth Day and all the stuff that happened in the '60s with the Hippies and everything really did, I think, have an affect on global awareness.
或许是因为 那时每个人产生环境意识 倡导地球日， 以及六十年代，这个嬉皮士时代发生的所有事情。 的确如此，我想，这对全球环境意识有一定影响。