riv‧er /ˈrɪvə $ -ər/ ●●● S2 W2 noun [countable] 1 a natural and
continuous flow of water in a long line across a country into the sea
→ streamthe Mississippi River
the River Thames
on a river
There were several boats on the river.
along a river
We went for a walk along the river.
up/down (a) river
a ship sailing up river
They drifted slowly down river.
across a river
a bridge across the river
GRAMMAR: Patterns with river
in the river • You use in the river to
talk about things that happen in the water:In summer we swim in the river.
There was something floating in the river.
on the river • You use on the river to talk about things that happen
on the surface of a river or very close to the edge of a river:We went boating on the river.
There’s a nice pub on the river.
GRAMMAR: Patterns with sea
in the sea
• You use in the sea to talk about things that happen in the
water:We paddled in the sea.
Whales are mammals that live in the sea.
on the sea
• You use on the sea to talk about things that happen on the
surface of the water:The boat floated on the calm sea.
by the sea
• You use by the sea to talk about things that are on the land near
the sea: They live in a cottage by the sea.
The dictionary says "The boat floated on the calm sea." but also says "There was something floating in the river."
My question is that, regarding to our swimming technique, sometimes we swim completely under the surface of the sea/ river (not diving though). In this case, do we say "we are swimming in the sea / river".?
Other times, we try to float our body on the surface of the sea/ river. In this case, do we say "we are swimming on the sea / river".?
Best Answer
It's always swimming in the water. Contrast a ship on the water, a submarine in the water. (Perhaps because we're entirely in the water, i.e. have approximately neutral buoyancy... but the true explanation may be over my head.)