Indeed, as the previous commenter noted, only auxiliary verbs get contracted. In fact, I believe you can think of main / auxiliary verb pairs as homographs, i.e. distinct words with different meaning and pronunciation but spelled the same. In general, main verbs are pronounced with a fully realized vowel sound, while auxiliary verbs get a weak vowel or schwa. For example,
"She said that she had had lunch already, and that that was the reason she wasn't hungry."
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Indeed, as the previous commenter noted, only auxiliary verbs get contracted. In fact, I believe you can think of main / auxiliary verb pairs as homographs, i.e. distinct words with different meaning and pronunciation but spelled the same. In general, main verbs are pronounced with a fully realized vowel sound, while auxiliary verbs get a weak vowel or schwa. For example,
"She said that she had had lunch already, and that that was the reason she wasn't hungry."
no subject