if only

[jack]

If only i had more time.
If only i have more time.

What is the difference between had and have? is the have or had one wrong? if so why, if it is right why?

If only i have a car, then i don't have to take the bus.
If only i had a car, then i don't have to take the bus.

What is the difference between had and have? is the had or have one wrong? if so why, if it is right why?

 

[MikeNewYork]

If only i had more time.
If only i have more time.

What is the difference between had and have? is the have or had one wrong? if so why, if it is right why?

If only i have a car, then i don't have to take the bus.
If only i had a car, then i don't have to take the bus.

What is the difference between had and have? is the had or have one wrong? if so why, if it is right why?

"If only" sets up the idea that what one is wishing for is "unreal" at the time of speaking. The speaker knows that he doesn't have more time or a car. Therefore, we use the past tense, because that tense is used for situations we know to be unreal.

More here: https://www.usingenglish.com/glossary/2nd-conditional.html

 

[jack]

I have done it.
I had done it.

What is the difference between the two in meaning?

 

[MikeNewYork]

I have done it.
I had done it.

What is the difference between the two in meaning?

In normal uses, the first (present perfect) is used for something that started in the past but is niot yet completed, something recently completed, or something completed in the past but still with relevance to the present.

The second is past perfect and is usually used for something completed in the past prior to another past action.

Your prior questions were about conditionals (if, if only) and the usage changes somewhat with conditionals.

More on conditionals here:

https://www.usingenglish.com/glossary/conditionals.html

 

[jack]

Antipollution laws had been in place since the beginning of the century.
Antipollution laws have been in place since the beginning of the century.


is "have" wrong?
what is the difference between the two in meaning by the use of had and have?

 

[Tdol]

They could both be used, depending on the context. Where you use the past perfect, there would have to be a subsequent event:

Although antipollution laws had been in place since the beginning of the century, they started drilling in the national park.

The present perfect would be describing a current situation:

Antipollution laws have been in place since the beginning of the century, so the application will be turned down.

;-)

 

[jack]

"Antipollution laws have been in place since the beginning of the century, so the application will be turned down. "
Doesn't this sentence have a subsequent event too?

Can you give me a scenario where i would use "have" and "had"
Lets say someone asked me this:

"How long have Joe lived in Canada?"
or do i say
"How long had Joe lived in Canada?"
How do i know which one to use?

Joe had been living in Canada for six years. <--is this incorrect?
Joe have been living in Canada for six years.
How do i know which one to use?



"They could both be used, depending on the context. Where you use the past perfect, there would have to be a subsequent event"
Do i use this rule when i ask questions too?