Because ducks stick their heads under water to feed and people duck their heads like ducks.

因为鸭子通常会将头埋到水里来喂食；而人们低头弯腰的样子和鸭子如出一辙。

youdao

youdao

Extensive flooding in the country has delayed planting and many crops are still under water.

该国大范围的洪水已经延误了栽种，许多庄稼现在还泡在水中。

《柯林斯英汉双解大词典》

The older kind of submarine used in World War Two could stay under water for only about forty-eight hours.

VOA: special.2010.06.11

I've got thirty-nine acres here and you can see it's all under about ten to twelve feet of water.

VOA: special.2010.05.17

I put Helen's hand under the cool water and formed the word w-a-t-e-r in her other hand.

VOA: special.2009.11.08

"In Chokwe, one of the hardest hit districts -- the normally vibrant streets now lie under water --all business brought to a standstill and social services shut down, " the United Nations said.

CNN: Raging floodwaters kill dozens in Mozambique

Gorges and karst plateaux feature 700 caves, hundreds of sinkholes, a 9-km-long thermal-water maze under a town and more than 1, 600 clear-water springs.

UNESCO: MEDIA SERVICES

To put up such a structure, working largely under sand-filled water, costs three to five times what it would on land for perhaps 50 years of life.

ECONOMIST: Musings on a favourite memento mori