英文释义

n North American republic containing 50 states - 48 conterminous states in North America plus Alaska in northwest North America and the Hawaiian Islands in the Pacific Ocean; achieved independence in 1776

n a base containing nitrogen that is found in RNA (but not in DNA) and derived from pyrimidine; pairs with adenine

n a heavy toxic silvery-white radioactive metallic element; occurs in many isotopes; used for nuclear fuels and nuclear weapons

n the 21st letter of the Roman alphabet