定积分 $\int \begin{array}{c}1\\ 0\end{array}\left(\sqrt{1-{\left(x-1\right)}^2}-x\right)dx$ 等于（   ）

阅读理解

                                                                                             (B)

       For the British, the home is private place in which he or she goes to hide away from the troubles of life. It is very seldom that one would be invited to a British person's home. It is rude to knock on a person's door if you are not invited. If you are invited, don't ask to see more than the downstairs that your British host invites you into. Never ask how much the house or any of the items in if cost.
       To the American, most of them want their home to be a place where they can entertain (款待) and share their lives with their friends. They may be delighted to give you a full tour of their houses. They may also be pleased when you show your interest and pleasure in their houses.
       Both British and American people will engage in quite a bit of chat and a drink or two before the meal is served. After the first mouthful, you should say how delicious the food is and ask something about it. Remember, never eat with your mouth open and make very little noise while eating. It would be nice of you to help your host in any way. Maybe offer to pour some drinks or clear up after the meal.

某同学不小心划破手指并少量出血，在伤口自动止血中起主要作用的血细胞是（ ）

为了探究“丁香提取液对马铃薯呼吸作用强度的影响”，某兴趣小组做了以下实验：

步骤 I：选取体积大小相近、薯皮未损伤、其它状况相同的马铃薯，分为16等份，4份为一组，分别均匀喷洒等质量的不同溶质质量分数的丁香提取液和清水（见下表），放在阴凉通风处迅速晾干．

步骤 II：把经过预处理的马铃薯用网袋装好后，放在温度为12℃、湿度为50%的恒温恒湿培养箱中储藏180天，储藏期间每隔45天各取出一组样品测定其呼吸作用强度，并绘图（呼吸作用强度表示每千克马铃薯每小时减少的质量为多少毫克）．请回答：