Question regarding introductory rites of the Mass

[Lava58]

While I was studying the Novus Ordo in Latin I noticed that there are 3 different type of greetings and 3 different types of penitential rites. Can the greetings and penitential rites be mixed together or do they have to match one another?

Example:

Greetings:

A: Gratia Domini nostri Iesu Christi, et caritas Dei, et communicatio Sancti Spritus sit cum omnibus vobis. Et cum spiritu tuo.

B. Gratia vobis et pax a Deo Patre nostro et Domino Iesu Christo. Benedictus Deus et Pater Domini nostri Iesu Christi.

C. Pax vobis(bishop) Dominus vobiscum(normal)
Et cum spiritu tuo

Penitential Rites:

A: Fratres, agnoscamus peccata nostra, ut apti simus ad sacra mysteria celebranda

Confiteor Deo omnipotenti et vobis fratres, quie peccavi nimis cogitatione, verbo, opere et omissione: mea culpa mea culpa mea maxima culpa. Ideo precor beatam Mariam semper Virginem, omnes Angelos et Sanctos, et vos, fratres, orare pro me ad Dominum Deum nostrum

Misereatur nostri omnipotens Deus et, dimissis peccatis nostris, perducat nos ad vitam aeternam. Amen

B: Miserere nostri, Domine
Quia peccavimus tibi
Ostende nobis, Domine, misericordiam tuam.
Et salutare tuum da nobis

C: Qui missus es sanare contritos corde: Kyrie eleison
Kyrie, eleison
Qui peccatores vocare venisti: Christe eleison.
Christe, eleison.
Qui ad dexteram Patris sedes, ad interpellandum pro nobis: Kyrie eleison.
Kyrie eleison.

Can the mass use form A with form C? Or must they match?

Why does one hear always form A of the Penitential rite?

I know that I omit the Kyrie if I used the Penitential Rite form C.

 

[AJV]

Mixed

 

[japhy]

Why does one hear always form A of the Penitential rite?

In my experience, form C of the penitential rite is more common than form A, and far more common than form B.

 

[Lava58]

Do other people who are trying to learn the Latin Mass memorize long passages such as the 4 different Eucharistic prayers? I only just recently began the study of the Latin Mass; and I found that I was able to commit to memory the introductory and penitential rites in about one week; and by this I mean being able to recite each word in its proper order. I don’t really know the grammar behind them; I didn’t memorize which of the 5 types of cases each noun fell into…etc.

If I continue at this rate, I will have covered the entire Mass, excluding the different prefaces, in about 6-7 months. I just keep the track on repeat while in the car, and spend about 30 min each day memorizing the passages. Is there really an excuse for the Latin Mass not being easy to understand? How can clergymen not find the time to memorize the Latin Mass?

Comments?