C.A.

名词 c.a.:

1. a white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals
   同义词：calcium, Ca, atomic number 20
2. a state in the western United States on the Pacific; the 3rd largest state; known for earthquakes
   同义词：California, Golden State, CA, Calif.