solemn

a.庄严的；严肃的；(指承诺)真诚的，正式的

soil, soiree, sojourn, sol, sol-fa, solace, solar, solar cell device, solar plexus, solar system, solarium, sold, solder, soldering-iron, soldier, soldierly (also soldier-like), soldiery, sole, solecism, solely, solemnity, solemnization, solemnisation, solemnize, solemnise, solemnly, solemnness, solenoid, Solent, solicit, solicitation, solicitor, Solicitor-General, solicitous, solicitously, solicitude, solid, solid-state, solidarity, solidification, solidify, solidity,