另两个为胸腺嘧啶和胞嘧啶, 即称为嘧啶的单环结构.The other two, thymine and cytosine, are single ring structures called pyrimidines.直到不久以前,人们对胸腺的功能尚不明了.The function of the thymus was unknown until relatively recently.动物的免疫系统由两个主要部分组成,即胸腺和骨髓系统.I...
Sam's mother said her son had a good upbringing and schooling.萨姆的母亲说她儿子家教好，受过良好教育。My mother, who had a sheltered upbringing, has fantastic memories of childhood.我妈妈在呵护下长大，对童年有着非常美好的回忆。I thought that my upbringing wa...
He was unsmiling and silent.他不苟言笑，沉默寡言。His eyes were hard and unsmiling.他目光严厉冷峻。She submitted to this scrutiny in unsmiling silence, patiently waiting for his next move.让他这么看着,刘玉英也不笑,也不说话, 耐烦地等待那结果....