u

u

名词 u:

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

同义词：uracil

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

同义词：uranium, atomic number 92

the 21st letter of the Roman alphabet

同义词：letter u

形容词 u:

(chiefly British) of or appropriate to the upper classes especially in language use