drop down

英文解釋：

動詞 drop down:

1. fall or drop to a lower place or level
   同義詞：sink, drop

相關對話：

1. The boat dropped down the river early the next morning.
   第二天一早小船就沿河向下游駛去了。
2. The fruit dropped down from the tree.
   水果從樹上掉下來。