descend、drop、fall与sink这些动词都表示“落下、下降”之意。
descend : 通常指沿斜线或斜坡下降。
- The plane began to descend.
飞机开始降落。 - The path descended steeply into the valley.
这条路很陡，一直通到山谷。 - Jane descended the stairs.
简走下了楼梯。
drop : 指物体从一定高度落下。
- She dropped her keys.
她把钥匙掉了。 - I'm always dropping things.
我总是掉东西。
fall与drop同义，指突然或猛烈地降落，但fall也可指任何下落，同高度或形式无关。
- The snow had been falling steadily all day.
雪持续下了一整天。 - It was October and the leaves had started to fall.
十月了，树叶开始掉落。
sink : 指在空气或水中垂直下降、下沉。
- The sun glowed red as it sank slowly below the horizon.
太阳缓缓沉到地平线下，发出红色的余辉。 - Student numbers have sunk considerably this year.
今年的学生人数大幅减少。
