Past perfect.

[Student33]

Hello,
I know that we use the past perfect when one action in the past happened before another past action, but do we always have to use it this way? I mean I am having difficulty in it's use especially after the following two verbs: (THOUGHT and BELIEVED) because the verbs that come after them seem to be further in the past, even though instantly e.g:
1.She dropped the book; I couldn't believe she (did/had done) it .
2.Sam put three spoons of sugar; I thought he (put/had put) to much.

Which is the correct tense in the previous examples?
Thank you very much:D

[Rusty]

Hello,
I know that we use the past perfect when one action in the past happened before another past action, but do we always have to use it this way? I mean I am having difficulty in it's use especially after the following two verbs: (THOUGHT and BELIEVED) because the verbs that come after them seem to be further in the past, even though instantly e.g:
1.She dropped the book; I couldn't believe she (did/had done) it .
2.Sam put three spoons of sugar; I thought he (put/had put) too much.

Which is the correct tense in the previous examples?
Thank you very much:D When the context of the sentence is such that the sequence of events is obvious the simple past is often used. In your sentences it is logical that dropped happened before believed and put three spoons of sugar happened before your thought. Using the past perfect you'd say: She had dropped the book; I couldn't believe that she had done that. It is much less wordy to use the simple past.