1. Because of increased physical fitness, life expectancy in the nation has risen to seventy—three years, with fewer people suffering from heart disease，the nation’s number one killer.

2. In the teaching of science and mathematics, the dominant mode of instruction is generally traditional, with teachers presenting formal lectures and students taking notes.

参考译文

1.【参考译文】因为人们的身体健康水平提高了，该国的人均寿命提高到73岁，而患心脏病 (作为头号杀手) 的人数也少了。

2.【参考译文】现在的理工科及数学的授课方式还是非常传统，主要就是老师在上面讲，学生在下面作笔记。