下面不属于故障恢复系统处理范围的是( )。 A．由于逻辑错误造成的事务失败 B．由

下列不属于阻火装置的是（）。

A、单向阀

B、安全液封

C、放空管

D、阻火闸门

能够引起酸雨的物质是（　　）

A．二氧化硫

B．二氧化碳

C．臭氧

D．粉尘

蟾酥的药用部位为（）。

案情：四达电脑公司与某显示屏生产厂家在2002年5月份签订一份合同，双方约定四达电脑公司应于同年7月份向显示屏生产厂家交付10台电脑，显示屏生产厂家则同时向四达电脑公司交付价值6万元的电脑显示屏。后来四达电脑公司企业转产不从事电脑行业，但由于过去业务上的来往欠某电脑营销商借款6万元，于是与该电脑营销商达成合意，由电脑营销商来接受显示屏生产厂家交付的电脑显示屏。四达电脑公司与电脑营销商达成协议后，四达电脑公司就此事通知了显示屏生产厂家，生产厂家表示到时会将电脑显示屏交给某电脑营销商企业。同年7月份，生产厂家已准备好应该交付给电脑营销商的电脑显示屏，但四达电脑公司却于此时未向生产厂家提供电脑。生产厂家于是对电脑营销商表示，除非四达电脑公司对其履行，否则为避免风险将不会对电脑营销商履行交付电脑显示屏的合同义务。电脑营销商此时才知道四达电脑公司与显示屏生产厂家之间的关系，表示这与他无关，双方发生争议。在收到显示屏生产厂家的抗辩后，电脑营销商找到四达电脑公司向其要求马上向显示屏生产厂家履行交付电脑义务，或者返还其欠款。四达电脑公司不同意，主张合同已签订，不能反悔，只说尽快履行其对显示屏生产厂家的债务。
根据上述案例，回答以下问题：
1.四达电脑公司与生产厂家之间的合同属于何种性质的合同

Mr Liu entered into an agreement to buy a second-hand car from Mr Feng at a price of RMB 50,000 yuan. After the conclusion of the agreement, Mr Liu paid the price and Feng delivered the car to Mr Liu. The two parties, however, did not register the sale of the car. Following the sale Mr Liu took the car to a repair shop to repair the air conditioner. After the completion of the repair and on the way home, a fire accident occurred due to the defect of the air conditioner and caused serious damage to the car. Mr Liu returned to the repair shop claiming compensation for the defect of the air conditioner. The repair shop insisted that it was not liable for the fire accident and the resulting damage to the car. In addition, after retrieval of the data from the local vehicles registration centre, the repair shop found that the registered owner of the car was still Mr Feng, not Mr Liu. Under such a situation it refused to discuss the dispute any more with Mr Liu, on the ground that he was not a legitimate owner of the car. When Mr Liu asked Mr Feng to negotiate with the repair shop, Mr Feng was reluctant to do so on the ground that the transaction between them was over since he had duly delivered the car to Mr Liu. Required: Answer the following questions in accordance with the relevant provisions of the Property Law, and give your reasons for your answer:

(b) state who should be the legitimate owner of the car; (4 marks)