One night, a mother and her daughter went out for dinner together. The mother was a heavy smoker, ____(make) her daughter feel very upset and worried. She would often tell her mother that smoking was very bad ____her health. But her mother wouldn't listen and refused to stop smoking.

    However, at ____(they) dinner that night, she noticed that her mother didn't have a single cigarette. As a matter of fact, she realized that she hadn't seen her mother smoke for ____ whole day.

    “I can see that you're not smoking at all today. Are you trying ____(give) up smoking?” the daughter asked hopefully.

    The mother answered, “No, I'm just feeling a little bit sick right now. I don't smoke ____(cigarette) when I'm sick, because if I do, it takes me ____(long) to get better.”

    The daughter____(reply), “Well, I guess you would____(probable) live a better life ____you got sick a bit more often!”

《九章算术》是我国古代内容极为丰富的数学名著。书中有下列问题“今有勾八步，股十五步。问勾中容圆径几何？”其意思为今有直角三角形，勾（短直角边）长为8步，股（长直角边）长为15步，问该直角三角形能容纳的圆形（内切圆）直径是____  步。

小明沿水平方向用10N的力拉着重50N的物体在水平面上做匀速直线运动，物体受到的摩擦力为____N，如果拉力增大到15N，物体受到的摩擦力____（选填“变大”、“变小”或“不变”），物体将作____（选填“匀速”或“变速”）直线运动．