During 2007, Big 4 Company’ s warehouse was totally destroyed by a tornado. Tornados are very rare in the region where Big 4 is located. The book value of the warehouse at the time of the tornado was 10 million and Big 4 is self-insured. In addition, on June 30, 2007, Big 4 acquired one of its major suppliers. The fair value of the net assets acquired by Big 4 was greater than the purchase price. According to International Financial Reporting Standards, should Big 4 recognize an extraordinary item for tornado damage and should Big 4 recognize negative goodwill on its balance sheet due to the acquisitionExtraordinary lossNegative goodwill（）①A.NoYes ②B. Yes No ③C.NoNo

A. ①

B. ②

C. ③

高速动车组车体通常采用（）和（）材料制造。