After the 1960 s, China began to inoculate BCG, pertussis, diphtheria, tetanus, measles and poliomyelitis vaccines.六十年代后, 中国开始在大、中城市接种卡介苗 、 百日咳 、 白喉 、 破伤风 、 麻疹、脊髓灰质炎的疫苗的工作.Anti-malarial vaccines are now under-going trial...
Prof. John Willis is our teacher of English.约翰·威利斯教授是我们的英语老师.I got into our dinghy while Willis took the helm and positioned the boat for the photograph.我钻进我们的小艇，威利斯掌舵，将船摆好位置准备拍照。Now, Mr. Willis . I'm sure that won&...