The book *lies/lay/is lying/was lying* open on the desk.

[z7655431]

I know the differences between "lie" and "lay" when they are in their original forms.
What I want to know is the word "lie" when it is used in different tenses.

a. The book lay open on the desk. (the past tense of "lie")
Does it mean the book is NOT on the desk now? (because it takes the past tense)
(But sentence e goes with the word "NOW", which is odd to me.)

What if I change it into other tenses?
b. The book lies open on the desk.
c. The book is lying open on the desk.
d. The book was lying open on the desk.
--What are the differences among them?
And I found the sentence in the Oxford Dictionary:
e. Much of the city now lay in ruins.
Though "lie" is in its past form, it goes with "NOW".
Does that mean much of the city is still NOW in ruins?
If so, why not it takes the present tense?
What if I change it into other tenses?
f. Much of the city now lies in ruins.
g. Much of the city is now lying in ruins.
And I also found the sentence in the Oxford Dictionary:
h. Too many apartments are lying vacant.

What if I change it into other tenses?
i. Too many apartments lay vacant.
Does it mean these apartments are not vacant now? (because it's in the past tense)
If so, why sentence e goes with the word NOW?

Most of these sentences are from Oxford Learner's Dictionaries.
Some of them are made by me.

I'm so confused.

 

[Charlie Bernstein]

Now can be placed in the past.

Example: I had worked hard all week, and now I was ready to go have fun.

 

[jutfrank]

a. The book lay open on the desk. (the past tense of "lie")
Does it mean the book is NOT on the desk now? (because it takes the past tense)

Not necessarily, no. Without relevant context, you shouldn't try to think of any use of the past tense as saying anything about the present.

What if I change it into other tenses?
b. The book lies open on the desk.
c. The book is lying open on the desk.
d. The book was lying open on the desk.
--What are the differences among them?

The only differences are the tenses they're in: present simple, present continuous, past continuous.

And I found the sentence in the Oxford Dictionary:
e. Much of the city now lay in ruins.
Though "lie" is in its past form, it goes with "NOW".
Does that mean much of the city is still NOW in ruins?
If so, why not it takes the present tense?

The verb lay is past tense, yes. The word now is probably a narrative device, meaning 'at that time (in the past)'.

What if I change it into other tenses?
f. Much of the city now lies in ruins.
g. Much of the city is now lying in ruins.

Yes, that's fine.

And I also found the sentence in the Oxford Dictionary:
h. Too many apartments are lying vacant.

What if I change it into other tenses?
i. Too many apartments lay vacant.

Fine.

Does it mean these apartments are not vacant now? (because it's in the past tense)

No.

If so, why sentence e goes with the word NOW?

I've answered that above. The word now sometimes means 'at that time (in the past)', especially in a historical narrative. Since the sentence is taken out of context, we can't be completely sure, but we can make a good guess that that is the case here.

 

[Rover_KE]

What if I change it into other tenses?
b. The book lies open on the desk.
c. The book is lying open on the desk.
d. The book was lying open on the desk.

--What are the differences [STRIKE]among[/STRIKE] between them?

There is a persistent but unfounded notion that between can be used only of two items and that among must be used for more than two. Between has been used of more than two since Old English; it is especially appropriate to denote a one-to-one relationship, regardless of the number of items.

(Merriam-Webster)