This picture shows that a cat is climbing a tree.

[diamondcutter]

This picture shows that a cat is climbing a tree.

I’d like to know if I could use this sentence to describe what I see in a picture.

 

[5jj]

No.

This picture shows a cat climbing a tree.

More natural would be This is a picture of a cat climbing a tree.

 

[diamondcutter]

The oil gauge shows that the car still has half a tank of oil.

This is also a self-made sentence. What do you think of it? Did I use the verb “show” correctly?

 

[emsr2d2]

That's fine. You can use "shows" or "indicates" there.

I've never had a car with an oil gauge. All of mine simply had a warning light that came on when I got low.

 

[diamondcutter]

What about a fuel gauge? Is it the correct term?

 

[tedmc]

What about a fuel gauge? Is it the correct term?

Yes, "fuel" refers to petrol while oil means lubricating oil

 

[Ostap]

I’d like to know if I could use this sentence to describe what I see in a picture.

You could use this sentence to prove that a cat was climbing a tree.

 

[5jj]

Not with the present tense.

 

[Ostap]

Not with the present tense.

Why?
This picture shows that a cat is climbing a tree. Therefore, this picture proves that a cat was climbing a tree.

 

[Rover_KE]

I've never had a car with an oil gauge.

Did you you never check your oil level with a dipstick?

 

[5jj]

This picture shows that a cat is climbing a tree. Therefore, this picture proves that a cat was climbing a tree.

Interesting logic.

 

[probus]

The oil gauge shows that the car still has half a tank of oil.

Although grammatically correct, this sentence is nonsensical. The oil in a car is not contained in a tank. It rests in the sump (or oilpan) below the engine. When the engine runs the rotating crankshaft splashes the oil up, and as it drains back down it lubricates the moving parts. Also, some engines have a pump that raises the oil from the sump.

 

[emsr2d2]

Did you you never check your oil level with a dipstick?

I did. I probably still should!

 

[diamondcutter]

Sorry, I meant to say this.
The fuel gauge shows that the car still has half a tank of petrol.
Does this sentence make sense?

 

[probus]

Yes, that sentence is fine.

 

[emsr2d2]

Sorry, I meant to say this.
The fuel gauge shows that the car still has half a tank of petrol.
Does this sentence make sense?

It's OK but I wouldn't mix "fuel" and "petrol". In the UK (where we use "petrol" where AmE speakers use "gas"), we call it a petrol gauge. You can shorten the sentence to "The petrol gauge still shows half a tank".