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
859÷43的商的最高位在______位上．
The reason _______ he was late again was that he was caught in a traffic jam.
A．which
B．in which
C．for which
D．of which
