30（）

A. Key disease carriers, such as insects and rats, thrive in crowded urban settings, further facilitating spread.
B. The unprecedented population densities in fourteenth-century Europe, for example, led to the plague outbreak that claimed the lives of one fourth of the population.
C. Although these infections are easily preventable if adequate water and sanitation are available, the vast majority of the world’s population are lifelong victims.
D. While new global markets have created unprecedented economic opportunities and growth, the health risks of our increasingly interconnected and fast-paced world continue to grow.
E. Pathogens can more readily establish in large populations, since all infectious diseases require a critical number of vulnerable individuals in order to take root and spread.
F. These areas can serve as a perpetual reservoir of disease or disease vectors, placing other parts of the city at risk of an outbreak and allowing the disease to continue evolving, often into a deadlier strain.

A. The new Minneapolis bridge joins a handful of "smart" bridges that have built-in sensors to monitor their health.
B. The kilometers of wire needed to connect sensors to central computers can add significantly to the system’s cost, according to Jerome Lynch of the University of Michigan, Ann Arbor.
C. By 2025 all bridges in America will have been equipped with this advanced technology.
D. A continuous skin would solve this problem.
E. In the wake of the catastrophe, there were calls to harness technology to avoid similar mishaps.
F. Engineers then installed additional weights as dampeners.