[Marian]

The following sentences I came across in grammar books and references, but some of them sound incorrect to me. I am not sure. I searched for a comprehensive descriptions on conditional sentences but couldn’t find any. I went through dozen of grammar books but none had good illustrations. If you found any mistakes, could you please point it out and explain its grammatical rules? I should be most grateful if you could just offer little help.


What’s the difference in the meaning between the following sentences? When do we use each form?

(1)
If you drive carefully, you will have fewer accidents.
If you drove carefully, you would not have so many accidents.

(2)
If you help me now, you are a true friend
If you helped me now, you would be a true friend

(3)
if she found a job, she will be happy.
If she found a job, she was happy.

(4)
if they didn’t show him the way, he will not find the right office
if they don’t show him the way, he will not find the right office.
If they didn’t show him the way, he wouldn’t find the right office

(5)
if it rains tomorrow, be sure to close the windows
if it should rain tomorrow, be sure to close the windows
if it is raining tomorrow, be sure to close the windows

(6)
if the truth were known, public opinion would change
if the truth were known, public opinion will change

(7)
if you don’t brush your teeth carefully, you will have many cavities.
If you didn’t brush your teeth carefully, you would have many cavities.
if you didn’t brush your teeth carefully, you will have many cavities.

(8)
Even if they offered to pay, I wouldn’t accept any money from them.
Even if they offer to pay, I will not accept any money from them.
Even if they offered to pay, I will not accept any money from them.

(9)
in case you want me, I’ll be in my office
in case you wanted me, I’ll be in my office

(10)
Without me to supplement your income, you wouldn’t be able to manage
Without me to supplement your income, you won’t be able to manage

(11)
if you ever touch me, I’ll scream
if you ever touched me, I would scream

(12)
She is taking a stick with her in case she has any trouble on the way
She is taking a stick with her in case she had any trouble on the way

(13)
if you believe that, you will believe anything
if you believed that, you would believe anything
if you believed that, you will believe anything

(14)
They sat on the grass if it was fine
They sat on the grass if it were fine

(15)
if it was raining, we usually stayed indoors.
If it rained, we usually stayed indoors.
If it rained, we would usually stay indoors
If it was raining, we would usually stay indoors

(16)
if the tap is dripping, it needs a new washer.
If the tap drips, it needs a new washer.

(17)
if nuclear weapons are employed in a world war, the world will be destroyed
if nuclear weapons were employed in a world war, the world would be destroyed

(18)
if anything happens, I’ll return immediately
if anything happened, I’ll return immediately
if anything should happen, I’ll return immediately

(19)
if anyone should come this way, we would be caught like rats in a trap
if anyone should come this way, we will be caught like rats in a trap
if anyone comes this way, we will be caught like rats in a trap

(20)
if he goes, I will go too.
If he were to go, I would go too
If he went, I would go too
If he goes, I would go too

(21)
The older men would find it difficult to get a job if they left the farm
The older men will find it difficult to get a job if they leave
The older men will find it difficult to get a job if they left

(22)
I should be surprised if it was less than five pounds
I should be surprised if it were less than five pounds

(23)
if you are in doubt, ask at your local library
if you were in doubt, ask at your local library

(24)
Whether I agreed or not, the search would take place
Whether I agreed or not, the search will take place
Whether I agree or not, the search will take place

(25)
Will he come if I shout?
Will he come if I shouted?
Would he come if I shouted?

(26)
Will you have enough time?
Would you have enough time?

(27)
He would come if you called
He would have come if you had called
He will come if you call

(28)
if I get an invitation, I’ll go there right away
if I got an invitation, I would go there right away

(29)
if it gets cold tonight, I will turn on the heating
if it got cold tonight, I would turn on the heating

(30)
I shouldn’t get to sleep at all if I lived next to that noise
I wouldn’t get to sleep at all if I lived next to that noise
I shouldn’t get to sleep at all if I live next to that noise

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