【简答题】The post-World War II period wasn t a peaceful one for America. The life of the 1950s was poisoned at the root by ______, and that of the sixties enriched by ______. Whereas______weighted all the time...
【单选题】Molting (换羽,脱毛) is one of the most involved processes of a bird's annual life cycle. Notwithstanding preening (梳理羽毛) and constant care, the marvelously complex structure of a bird' s feather inevitabl...