A: Great Question. During lent we refrain from saying or singing the Alleluia in the liturgy to remind us we are not in the state of rejoicing. The season of lent imitates the 40 days in the desert, which is a time of preparation and waiting. When Easter comes the "Alleluia" becomes more significant and exciting, just as chocolate is on Easter morning if it you sacrificed it for lent. Secondly, Sanctus means Holy in Latin, so when we say Sanctus we are referring to the beginning of the Eucharistic prayer when we say or sing:
Holy, Holy, Holy Lord, God of power and might, heaven and earth
are full of your glory. Hosanna in the highest.
Blessed is he who comes in the name of the Lord. Hosanna in the highest.
Sanctus, Sanctus, Sanctus Dominus Deus Sabaoth.
Pleni sunt caeli et terra gloria tua. Hosanna in excelsis.
Benedictus qui venit in nomine Domini. Hosanna in excelsis.
You can follow along with the Order of Mass in the front of the missalette, Celebrating the Eucharist. Unfortunately, the missalette does not have the Mass parts in Latin. A personal missalette, called the Magnificat, has the Order of Mass and the Latin Mass parts. A Magnificat would be a great resource to have for this and the daily readings and feast days. I love my Magnificat!
