【名偵探皮卡丘心平氣和】評論
Physical activity improves the function of many organ systems in the body, but the effects are usually linked to better athletic performance. For example, when you walk or run, your muscles demand more oxygen, and over time your cardiovascular system responds by building new blood vessels.(A) vessels n. 容器；船舶；血管（vessel的複數）(B) streams n. 溪流；流動；光線；潮流(C) circulars adj. 圓形的，環形的；迴圈的 n. 通知，通告(D) pressures n. 壓力