A．challenged the rights ofB．criticized the views ofC．in……

单项选择题The most important result of the Lewis and Clark expedition was that it enabled the United States to claim the Oregon region.

单项选择题The cylindrical shape of a cactus reduces moisture loss.

单项选择题By 1900, many municipalities had begun to restrict the use of automobiles in order to en- sure pedestrian safety.

单项选择题Over thirty cities around the world boast more than five million residents.

单项选择题Proper exercise plays a significant role in the rehabilitation of patients with various back ailments.