1,2,4,7,11,( ),22,( )。
16,29
In relation to securing civil obligations:
(a) Defi ne the term ‘mortgage’. (2 marks)
下列哪种钢材的性能最优良()。
A.沸腾钢
B.镇静钢
C.半镇静钢
D.特殊镇静钢