门口站着一位穿戴整齐、仪态庄重的男子。At the door was a neatly dressed, dignified man.她依然仪态优雅，不失风度。She had not lost her grace and style.她是一位仪态优雅的佳丽.She is a beautiful girl with the grace and poise....
氚是最和缓的放射性同位素之一.Tritium is one of the mildest radioactive isotopes.更为活跃的是氢的较重同位素, 氘和氚.More reactive are the heavier isotopes of hydrogen, deuterium and tritium.氚肺扫描可能有助于早期诊断吸入性损伤.Xenon lung scans may be helpful in the ear...