Cook speculated that this phenomenon, which became known as the black-drop effect, was caused by "an atmosphere or dusky cloud round the body of the planet."
这个现象后来被称为「黑滴效应」，库克猜测是由「金星周围的大气或尘埃云」造成的。
2
Over half of black males in the inner cities drop out of school without graduating.
城市贫民区有超出半数的男性黑人毕业前离校；
3
When you see the black arrow display on the left of the edge and the narrow bounding rectangle, as shown in figure 8, drop the component.