第25题: [单项选择]—Do you know what Tom does all day —I know he spends at least as much time watching TV as he______his lessons. A. is doing B. does C. spends to do D. does doing 参考答案:D 答案解析:[解析] does代替前面出现的谓语动词spends time doing sth,故答案为D。
第39题: [单项选择]If the capacity of a centrifugal pump decreases gradually over a long period of time, you should replace the (). A. packing gland B. mechanical seals C. lantern rings D. wearing rings 参考答案:D