11.5.3 Formation of the mais-que-perfeito composto
The mais-que-perfeito composto is perhaps the only tense that is used the same way in any language. Although most of the descriptions of its use we find in grammar books are wrong, people use it always corrrectly.
The event, actions, processes are not told in the correct chronological order.
I couldn't pay the bill, I had lost my wallet.
not: I couldn't pay the bill, I lost my wallet.
not: I couldn't pay the bill, I have lost my wallet.
The mais assertion of the sentence is the fact that an action, event, process is terminated
He had not studied and therefore he didn't pass the exam.
no: He didn't study and therefore he didn't pass the exam.
no: He has not studied and therefore he didn't pass the exam.
The only thing that may astonish is the fact that the past perfect, which is used in a well defined context, is always described wrong. The anteriority to a period of time in the past doesn't require the past perfect, see 11.3.
The formation is easy. It is formed with the imperfeito of the auxiliary verb ter and the past participle, in other words the same way as the English past perfect.
Conjugate the following verbs in mais-que-perfeito composto.