油层吸水能力及其变化，井下配水工具的工作状况，可以通过指示曲线形状和曲线斜率变化来判断。
参考答案：对
—Do you often exercise?
—Yes. I think exercising helps us ______. [ ]
A. keeping healthy
B. to keep health
C. keeping in good health
D. to keep in good health
底片处理时遭弯折损伤，会在底片上出现黑色类似手指掐伤的痕迹，这是何时发生弯折而引起的？（）
A、曝光前
B、曝光后
C、定影后
D、不一定
