焦油加工的主要任务是获得酚、萘、蒽等纯产品和()等粗产品。
参考答案:洗油沥青
We work together to achieve our common purpose: _____ world that is safer, cleaner and healthier than _____
one we found. [ ]
A. the; the
B. a; 不填
C. a; the
D. the; 不填
简述盘状红斑狼疮的皮损及临床表现。