第8题: [单项选择]用肺表面活性物质治疗肺透明膜病,下列哪项是正确的() A. 气管内给药,每次60~200mg/kg,可用2~4次 B. 人工合成制剂较天然制剂好 C. 对可能发病的早产儿,表面活性物质没有预防作用 D. 表面活性物质不能从羊水中提取出来 E. 目前表面活性物质只能从牛肺中提取 参考答案:A
第13题: [单项选择]______ so many efforts in such a short period of time. A. Never have any student made B. Never have a student made C. Never has any student made D. Never did a student make 参考答案:C 答案解析:本题考查句子结构。当带有否定意思的副同放在句首时,其后的句子要倒装;时间状语为in a short period of time,用完成时;student为单数,用has。该句意为:从没有一个学生能在