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I'd like you to tell me if my understanding of the following sentences, below, is correct.

1. If I knew she is coming, I would go to welcome her at the airport.
2. If I knew she was coming, I would go to welcome her at the airport.
3. If I knew she was coming, I would have gone to welcome her at the airport.
4. If I had known she was coming, I would have gone to welcome her at the airport.


1. If I knew she is coming, I would go to welcome her at the airport.

This implies that I don't know if she is coming or not, and her coming is still an upcoming event. So, if I get to know that she is coming I certainly will go to the airport to welcome her.

2. If I knew she was coming, I would go to welcome her at the airport.

This implies that I don't know if she was coming or not, and also her coming already might have taken place or still is an upcoming event.

3. If I knew she was coming, I would have gone to welcome her at the airport.
4. If I had known Mary was coming, I would have gone to the the airport to welcome her.


These imply that I did not know about her coming and I did not go to the airport to welcome her.


Both sentences # 3 and 4 are correct, and imply that the event (her coming) already has taken place; and I did not know about her coming. # 3 sentence is simpler, and a lot of Americans say "choose a simpler form if it means the same thing."
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Only these are correct:

2. If I knew she was coming, I would go to welcome her at the airport. = I don't know that she's coming now or in the future.
4. If I had known she was coming, I would have gone to welcome her at the airport. = I didn't know that she was coming in the past.

Your third choice is:

If I know she's coming, I will go to welcome her at the airport. = I may find out that she is coming.

Your other sentences are misconstructed.
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MM:

Your opinion would be appreciated in this related thread:
tenses
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There seem to be plenty of opinions over there already, Marius. I believe I will just stick to my own, here.
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Thank you Mister Micawber.


Vivaldi,

If I know she is coming, I will go to welcome her. (next week)

( The structure seems present but you are talking about a possibility in the future. You may learn that she is coming)

If I knew she was coming, I would go to welcome her. (now)

(The structure seems past but you are talking about a present imaginary situation. You don't know if she is coming)

If I had known she was coming, I would have gone to welcome her. (last week)

(You are talking about a past situation. You didn't know she was coming, you didn't go to welcome her.)

Hope it's clear..

Understanding the actual process (Related part of authorization of Purchase requisition)

The process mainly starts when the asset is required the user department. The process as follows :

1) When the asset requires the user department needs to take written approval from the user department head / Business unit head;

2) Approval is passed to general store & they made a purchase Requisition (PR) through SAP and PR number is automatically generated in SAP;

3) PR is forwarded to Corporate purchase department through SAP. For only ISML, Hard copy PR with authorized signature by User department head, Business unit Head is also send to them;

4) After getting PR, purchase department analyses Vendor considering quality , price & other specification and make comparative statement;

5) After finalising Vendor, purchase department makes Purchase order in SAP by inserting purchase requisition number;

6) Then PO is realised by business unit head through SAP If the amount crossed 100,000 BDT CEO needs to release it.

Specific Control Weaknesses

Possible weakness have been identified during our audit procedure :

ØWhen the PR is forwarded to Corporate purchase department through SAP no review is made through SAP. (see process no. 3)

ØIn SAP, there is no option to release Purchase requisition.

ØWhen the PR is uploaded in SAP there is no review of upper hierarchy.

Ø

Impact of Control Weaknesses

ØIf the PR is not reviewed by upper hierarchy then there is a chance of purchase unnecessary assets.

ØIn the organization the asset is always a high value, so if the reviewed is not conducted the management do no know the who wanted the item and who said that it could be purchased in initial stage.

ØIt may also occurs override of controls.

ØVendor selection in line with quality, quantity, model and preparing comparative statement is long process before creating PO which needed enough time to prepare but If the PO is not approved by upper hierarchy then entire time will be wasted.

Ø

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