若函数f（x）=x³+x²﹣2x﹣2的一个正数零点附近的函数值用二分法逐次计算，参考数据如下表：

那么方程x³+x²﹣2x﹣2=0的一个近似根（精确到0.1）为（　　）

子弹水平射入静止在光滑的水平面上木块中，进入木块的最大深度为d．若在子弹深入木块直到最大深度的过程中，木块沿桌面移动距离为L，木块对子弹平均阻力大小为f，那么在这一过程中，阻力对子弹的功为____，木块获得的动能为____．

    You may think, salt is just a simple cooking element we shake on our food for a little extra taste. But salt is much more than that. Without salt our muscles would not move. Our nervous systems would not operate. Our hearts would not beat.

    But do not think rubbing salt in a wound will help. Doing that would be painful and not heal the wound. To rub salt in a wound is an idiom that means to purposefully make a bad situation worse.

    Early humans got the salt they needed to stay alive from the animals they killed. But advances in agriculture led to a diet low in salt. So, humans needed to find other sources. Those who lived near the ocean or other natural sources for salt were lucky. Those who did not had to trade for salt. In fact, people used salt as a method of payment in many parts of the ancient world. The word “salary” comes from the word “salt”.

    Salt also played an important part in population movement and world exploration. Explorers understood that if they could keep food fresh, they could travel longer distances. So they used salt to preserve food and explored the world.

    Salt was so important that, according to food historians, it was traded pound-for- pound for gold. Today, people still use the expressions “to be worth one's salt” or “worth one's weight in salt”. The expressions describe a person of value.

    A person might also be called “salt of the earth”. That description means he or she is dependable and trustworthy. However, when you say “I think we should take what he said with a grain of salt” you mean you accept it but maintain a degree of doubt about its truth.