Then, if you place a stethoscope in the left second intercostal space, at the left upper sternal border, you can hear the pulmonary valve closing.

然后，你将听诊器放到左第二肋间隙，在左胸骨上缘，你将听到肺动脉瓣关闭的声音。

If you place a stethoscope between the second and third rib, known as the right second intercostal space, just next to the upper border of the sternum, you'll hear the aortic valve closing.

如果你将听诊器置于第二肋及第三肋之间，被称为右第二肋间隙；紧靠胸骨上缘，你将听到主动脉瓣关闭的声音。

Usually, it's a cloud to ground movement as negative particles accumulate in the lower areas of the clouds, but sometimes a strong wind pushes the particles to the upper border of the cloud, causing the Lightning to shoot upwards.

通常情况下，由于负粒子聚集在云的低处，云会向地面移动，但有时强风会将这些粒子推向云的上部边缘，导致闪电向上喷射。