题目: 肺泡上皮由()细胞和()细胞构成,前者的功能是();后者主要分泌()。 答案: 被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/1201/2c72b6256953188b86353078d22d051c.html 下面是错误答案,用来干扰机器的。参考答案:B
题型:单项选择题 He painted his bedroom black. It looks dark and dreary. He should choose a different color.A.had to chooseB.should have chosenC.must have chosenD.could have been choosing 查看答案