完形填空

    What do you do at the weekends? Some people like to1 at home. But others like to go for a walk2 play football. My friend Jack works hard in a factory on3. At the weekends he always 4 different things. On Saturday he5 his car and on6 he goes with his family to a village by car. His uncle and aunt have a farm there. It's not a7 one, but there's always8 to do on the farm. The children help with the animals and give them their9. Jack and his wife help in the field. At the end of the day, they are all10 and want to have a big meat very much.

下列字形有两个错别字的一项是（    ）

三氧化二镍（Ni₂O₃）是一种重要的电子元件材料和蓄电池材料．工业上利用含镍废料（镍、铁、钙、镁合金为主）制取草酸镍（NiC₂O₄•2H₂O），再高温煅烧草酸镍制取三氧化二镍．已知草酸的钙、镁、镍盐均难溶于水．工艺流程图如所示．

请回答下列问题：

如图，扇形AOB的面积，占圆O面积的15%，则扇形AOB的圆心角的度数是____．

医生给心脏疾病的患者做手术时，往往要用一种称为“人工心脏泵”（血泵）的体外装置来代替心脏，以推动血液循环．如图是该装置的示意图，线圈AB固定在用软铁制成的活塞柄上（相当于一个电磁铁），通电时线圈与活塞柄组成的系统与固定在左侧的磁体相互作用，从而带动活塞运动．活塞筒通过阀门与血管相通，阀门S₁只能向外开启，S₂只能向内开启．线圈中的电流从B流向A时，螺线管的左边是____极，血液从____流入____．（后2空选填①、②、③）．