tense - Is it possible to be grammatically correct without using past perfect?

Can you guys please help with which verb tense to use when talking about numerous specific events?

In the example below, I'm not quite sure if past perfect really is necessary.

"She sent me a new book as soon as I finished the book."

"She sent me a new book as soon as I had finished the book"

Then in the example below, I'm not sure if it will be incorrect without using past tense.

"Do you remember when my son got sick last Tuesday and I had to go pick him up? That's why I got worried when his teacher called me this morning."

"Do you remember when my son had gotten sick last Tuesday and I had had to go pick him up? That's why I got worried when his teacher called me this morning."

In the example below, I'm not even sure how to change it into past perfect. Maybe it's because it is not necessary at all?

"He said that the moment he first met her, he felt something special and began to keep a diary."

Edit: I don't really understand the answer that was given to me.

Why should I use past perfect at all in my "Do you remember when my son got sick" example? Am I not explaining things in chronological order? I thought I was starting to grasp this past perfect thing, but now I'm even more confused.

Also, Why is it not "He said that the moment he had first met her, he had felt something and had begun to keep a diary"?

Didn't the meeting take place before his saying it? Or is "first met her" modifying what kind of moment it was? Also, didn't the "feeling something" and "beginning to keep a diary" happen simultaneously?

Answer

1. The first question is about the tense we should use after "as soon as". In a sentence such as this:

I had left when the phone rang.

you need to use the past perfect in the second clause to show which action came first and which – second. However, when you use “as soon as”, the sequence is clear and it is normally a matter of preference which one to use, so both your examples will be correct. In American English the preference would normally be past simple. The past perfect would emphasize the fact that one action was complete before the other one occurred. (an explanation given in Grammar for Teachers by Andrea DeCapua)

2. In the second pair of examples they are both correct again. It is unnecessary to use past perfect because the time is mentioned and the sequence of events is clear. Also, the actions are described in the order in which they occurred. You can use the past perfect if you want, to emphasize that one was before the other.

3. The third question was about the sentence

He said that the moment he first met her, he felt something special and began to keep a diary.

The actual words the man said must have been:

"The moment I first met her, I felt something special and began to keep a diary."

When you report his words and begin with “He said”, the entire phrase shifts one tense back and becomes:

He said that the moment he had first met her, he had felt something special and had begun to keep a diary.

Although this is the grammatically correct sentence, it is very common that the past simple does not become past perfect in indirect speech. When reporting, native speakers tend to make present tenses past ("I am studying" - "She said she was studying") but very often do not care to make the past tenses perfect, as grammar books always teach us we should.

That is what makes both these sentences correct: "He said that the moment he first met her, he felt something special and began to keep a diary." and “He said that the moment he had first met her, he had felt something special and had begun to keep a diary.” (have a look at the end of this page)