金属材料已得到越来越广泛的应用，请依据所学知识回答下列问题．

________ a high percentage of Australians may be people who watch sports rather than do them, as far as most of its population is concerned, it is indeed a great sporting nation.

—— ____important it is to study English well! Do you think so ?
——Yes, I agree with you.

有些公共汽车配备逃生锤，遇到紧急情况时，乘客可以用逃生锤打破车窗玻璃逃生．为了更容易打破玻璃，逃生锤外形应选择图中的（   ）

林则徐是影响中国近代化进程的重要人物之一，学术界对其研究颇多。下列对此研究最有史料价值的材料是                       （   ）