A cold is an infection of the upper respiratory tract.感冒是上呼吸道的感染。She produced a feminist tract, "Comments on Birth-Control", in 1930.她1930年写了篇女性主义的短文《论节育》。A vast tract of land is ready for development.一大片广阔的土地可待开发。...
Bacteriophage ( phage ) A virus that infects bacteria.噬菌体 :感染细菌的病毒....a simian virus.一种猴病毒the ability of the virus to mutate into new forms病毒变异成新菌株的能力human immunodeficiency virus or HIV人体免疫缺陷病毒，即HIVObjective : To establi...
She took a playful swipe at her brother.她玩笑般地朝她弟弟挥手打去.Her manner is playful and girlish.她举止像少女般顽皮。...a playful fight...嬉戏的打闹They make a playful thing of me,use me for their amusement.他们拿我当活宝,利用我给他们找乐子。...a playful puppy....