It was previously suggested that growth in the midribs might provide enough internal stress for the petals to burst out of their casing.
过去人们认为是花瓣中脉的生长产生了足够的内部张力让花瓣从花蕾中伸展开来。
3
Start moving. A quick burst of aerobic exercise relieves stress and improves concentration by flooding the brain with oxygen and activating brain chemicals such as dopamine.