第6题: [单项选择]The period of a lighted aid to navigation refers to the（）. A. date of construction or establishment B. length of time between flashes of the light C. time required for the longest flash of each cycle D. time required for the light to complete each cycle 参考答案:D
第20题: [单项选择]有关盆腔脓肿的治疗错误的是（） A. 盆腔脓肿未形成时，应以药物为主，辅以物理疗法 B. 小脓肿可采用非手术治疗 C. 脓肿较大时，须手术治疗 D. 可采用经腹腔排脓 E. 已婚妇女可采用后穹隆途径排脓 参考答案:D 答案解析:盆腔炎症尚未形成脓肿时，应积极全身治疗，给予有效抗生素，辅以温热盐水灌肠和物理透热疗法，多可自行吸收消散。若形成脓肿，如脓肿较小也有自行吸收的可能性。如脓肿较大，经一段抗感染治疗后收效不显著，应考虑手
A. there are more ways to ensure blood supply. B. more ways should be developed. C. new rules should be developed. D. more blood supply should be called for. 参考答案:B 答案解析:[听力原文] The new rules call for blood centres to develop more ways to make sure the country's blood
