历史上“蜀遭难,难于上青天”,如今“蜀道不再难”得益于( )
A:环境变迁
B:人口增多
C:科技进步
D:民族团结
下列句子中没有通假字的一项是( )
—______ does your cousin usually go to work on foot?—He says it's good for his health.