Listen to this version of "Every Breath You Take" by The Police, performed in a bossa nova style by Karen Souza. The structure is laid out below. It is virtually identical to the original version.
The first double verse is heard from the beginning
The chorus is heard from 0'31
Another verse is heard from 0'48
The bridge is heard from 1'05
The verse chords are heard from 1'25 in an electric guitar solo
The second chorus is heard from 1'40
The final verse is heard from 1'56 with the final line repeated while the music fades out. Repeating the final line is called a tag
Having at least two distinct sections in a song allows it to have a sense of cohesion and variation. An instrumental solo can be a really good way of having a "break" from the singing, producing more contrast.
Samba Em Preludio has a simple structure outlined here:
Introduction (just bass guitar)
A double verse from bar 4 (0'16)
A double verse with a different melody heard from bar 23 (1'19), which is where the bossa nova comes in
An acoustic guitar solo heard for 32 bars from bar 55 (2'26)
Another double verse heard from bar 88 (3'35) with the final line repeated twice in a tag
The structure of the song is very comparable to Every Breath You Take although neither of the verses can really be called a chorus because they don't feel climactic or have a distinct sense of arrival. This suits the relaxed and almost plaintive quality of the song well.