油品损耗是因液体的蒸发以及装液容器难以避免的洒漏等原因而产生的。
参考答案：对
She sat at her desk, with her eyes ________ on the book, ________ in its plot. [ ]
A. fixing; absorbing
B. fixed; absorbed
C. fixed; absorbing
D. fixing; absorbed
计算，使结果中只含正整数指数幂：（a-3b-2）-2•（a-1b3）-3=______．
