题目: ____ their work, they had a rest. [ ]A. Having finished B. Finished C. Having been finished D. Finishing 答案: 答案:A
题型:选择题 鲨鱼是目前发现的唯一不患癌症的动物,其体内含有一种抗癌物质:C30H50 ,关于该物质的说法正确的是 [ ]A.该物质是一种混合物B.该物质由30个碳原子和50个氢原子构成 C.该物质的相对分子质量是410 D.该物质是目前发现的唯一一种治癌药物 查看答案