1. The biggest obstacle for many parents, they say, is to realize their own weaknesses.
    他们说，对许多家长而言，最困难的是让他们意识到自己的不足。

2. "The animals that learned to go through the obstacle course exhibited a greater number of brain connections than the animals in the exercised or inactive groups," Greenough said.
    "与跑动的和不运动的老鼠相比，经过越障训练的老鼠脑神经联结数更多。" 格里诺说，

3. Our next obstacle was a shallow pool of water about half a mile across.
    下一个障碍是一片约半英里宽的浅水塘。

4. One group was exercised by running inside an automatic wheel, a second group improved their skills in a complicated obstacle course, and a third group was inactive.
    第一组在自动轮中跑动，第二组通过一种复杂的越障训练来提高技能，第三组则不做任何运动。