Which Tense is Correct?

Question

Are these sentences both grammatically correct? If they are both grammatically correct, what's the difference in meanings?

Case A:
If the fuel is not full, the engine will stop./If the fuel is full, the engine will not stop.

Case B:
If the fuel is not full, the engine stops./If the fuel is full, the engine does not stop.

Hoa Thai · Accepted Answer

GoriAre these sentences both grammatically correct? If they are both grammatically correct, what's the difference in meanings?

Case A:
If the fuel is not full, the engine will stop./If the fuel is full, the engine will not stop.

Case B:
If the fuel is not full, the engine stops./If the fuel is full, the engine does not stop.

Hi,

Grammatically, all four sentences are fine.
Semantically, all of them have two common logical problems. The first one is: full is associated with a container not the fuel itself. Assuming that you mean a fuel tank not the fuel itself, we still have one more logical problem: for a fuel tank, not full does not mean empty. All four statements convey an illogical message. As soon as I read them, I feel like the engine would stop right after its start since partially full is not full.

That said, let's change your sentences as follows:

Case A:
If the fuel tank is empty, the engine will stop./If the fuel tank is not empty, the engine will not stop.

Case B:
If the fuel tank is empty, the engine stops./If the fuel tank is not empty, the engine does not stop.
In terms of verb-tense usage, there is no much difference between the usage of the 'present tense' and 'will' except part B states fact, while part A talks about eventuality (i.e., sometime in the future). Since there is not much difference between the two cases, let's see if there is any differences in the meaning between the two sentences in either case. Take B as an example; the first sentence is natural. That is how normal people think. The second sentence sounds odd, because it sends a message that the engines keeps running as long as the the tank is not empty! It triggers many more questions such as: "What would / will happen if we cut the electrical power? "

Anyway, I think my interpretation is debatable in terms of engine mechanics. However, I hope it makes sense to you.

Anonymous · Answer

I see, so there is not much difference between these two cases.  Therefore, I can use either case anyway, in terms of verb-tense usage.  Is my understanding correct?

Hoa Thai · Answer

AnonymousI see, so there is not much difference between these two cases. Therefore, I can use either case anyway, in terms of verb-tense usage. Is my understanding correct?

Hi,
Not much in the context of the original post. However, as I stated in my previous post, 'will' means 'sometime in the future'. If we want to state fact, which is true at all time, we use the present tense. Note that we can also use 'will' for prediction as in "It wll rain tomorrow." And if we attach 'be' to 'will', we send a message of firm decision as in "I will be there."

Gori · Answer

Dear Hoa Thai,

Thank you for your comments.

Which Tense is Correct?

Top answer

Get the Weekly English Kit 📬

Related Questions