Poly ( vinyl alcohol ) has been protected against radiation by benzalation and benzoylation.聚乙烯醇 的耐辐解可通地苄叉化和苯甲酰化提高.Poly alcohol has been protected against radiation by benzalation and benzoylation.聚乙烯醇的耐辐解可通过苄叉化和苯甲酰化提高.M...
他正挥手以引起他们的注意。He was waving his arms to draw their attention.学院的老师们抱怨说他们的学生还很不适应大学的课业。Faculty members complain that their students are unprepared to do college-level work.马克走在前面,听不见他们的声音。Mark was out of earshot, walking a...