Both the simple past went and the past perfect had
gone are possible in the sentences you give.
It is more formal, and also doubly accurate, to use the past perfect,
||I said (for example, at 11:00 a.m.
today) that Paul had gone (previous to 11:00 a.m.
today) to the movies yesterday.
It is also perfectly understandable and acceptable in informal speech
and writing, to use the simple past, as in:
||I said that Paul went
to the movies yesterday.
Sentence (b) is clear because of the time word yesterday.
In fact, the past perfect in this particular sentence, as in sentence
(a), sounds artificial, especially with the time word yesterday,
and so in fact, sentence (b) is the better choice. The sentences appear
to be conversational, and, particularly in conversation, and particularly
with the use of the time word, the simple past is appropriate.
I think it’s unlikely that a reputable testing company would
have both these possibilities as answers. If, however, you find them
on an individually made test, you might assume that the teacher is looking
for the more formal answer, using the past perfect in the reported speech.
In Understanding and Using English Grammar, Third Edition
(Longman, 1999), Betty Azar writes: " …sometimes in spoken
English, no change is made in the noun clause verb, especially if the
speaker is reporting something immediately or soon after it was said"
There are instances, however, where you really have to choose either
the past perfect or the simple past in the reported sentence, in order
to be accurate. Look at these sentences. Let us assume that Bryan asked
the question earlier today, at 11:00 a.m. Note that there is no time
expression in the sentences to clarify the time periods Bryan is asking
(c) Bryan asked me where Pamela was.
(d) Bryan asked me where Pamela had been.
In sentence (c), Bryan’s asking took place at the same time as
Pamela’s being somewhere; in other words, he wanted to know (at
11:00 a.m.) Pamela’s location at that same time (also at 11:00
In sentence (d), Bryan wanted to know (at 11:00 a.m.) about Pamela’s
location previous to his asking time, perhaps the night before,
or at 9:00 a.m. today. At the moment of asking, Brian wanted information
about Pamela’s earlier location.
If there is no time word in the dependent noun clause (where Pamela
was / where Pamela had been), or the context does not make the
time clear, it is important to show a time differentiation. Here, there
is a difference in the time referred to in sentence (c) — 11:00
a.m. this morning — and sentence (d) — a time before 11:00
a.m. this morning. In sentence (c), the simple past is used to refer
to Pamela’s location at the same time that Bryan asked the question;
in sentence (d), the past perfect is if Bryan wants to know Pamela’s
location at the same time he asked the question.
More often, however, the past perfect is not called for.
See Marilyn’s comments.
Additional comments from Burkhard Leuschner