Past tense in Sindarin covers almost all forms of past tense in English. I watched; I have watched; I have been watching - these are all translated the same way.

Past Tense for A-verbs

Normally, the past tense is made by adding (-nne) to a verb root, then adding the pronoun suffix.
For Example: the root (cuia-)
I lived. - Cuiannen.
We lived. - Cuiannem.
You lived. - Cuiannech.
You lived. - Cuiannel.
They lived. - Cuianner.

The third person singular is different. Add (-nt) onto the root.
He or she lived. - E cuiant.

For A-verbs ending in (-nna), the A is taken off and an E is added.
For Example: the root (danna-)
I fell. - Dannen.
We fell. - Dannem.
You fell. - Dannech.
You fell. - Dannel.
They fell. - Danner.

The third person singular is the same as in the regular A-verb.
He or she fell. - E dannant.

For A-verbs ending in (-ada), the -da is taken off and (-nne) is added.
For Example: the root (pada-)
I walked. - Pannen.
We walked. - Pannem.
You walked. - Pannech.
You walked. - Pannel.
They walked. - Panner.

For the third person singular, the (-ada) becomes (-ant).
He or she walked. - E pant.

For A-verbs ending in (-va), the -va is taken off and (-mme) is added.
For Example: the root (drava-)
I hewed. - Drammen.
We hewed. - Drammem.
You hewed. - Drammech.
You hewed. - Drammel.
They hewed. - Drammer.

For the third person singular, the (-va) becomes (-mp).
He or she hewed. - E dramp.

Past Tense for I-verbs

The I-verb past tense is very complicated, so I'll go over the third person singular first, then the rest. For the third person singular, the end of the root is all that changes. For the rest, treat the vowels as though they are non-final vowels in a plural, change the ending consonant, and add an I to the end.

For verb roots ending in B, the B becomes (-mp) for third person singular and (-mmi-) for the rest.
Example: From the verb root (hab-):
He or she clothed. - E hamp.
I clothed. - Hemmin.
We clothed. - Hemmim.
You clothed. - Hemmich.
You clothed. - Hemmil.
They clothed. - Hemmir.

For verb roots ending in D, the D becomes (-nt) for third person singular and (-nni-) for the rest.
Example: From the verb root (echad-):
He or she made. - E echant.
I made. - Echennin.
We made. - Echennim.
You made. - Echennich.
You made. - Echennil.
They made. - Echennir.

For verb roots ending in DH, the DH becomes (-nn) for third person singular and (-nni-) for the rest.
Example: From the verb root (neledh-):
He or she entered. - E nelenn.
I entered. - Nelennin.
We entered. - Nelennim.
You entered. - Nelennich.
You entered. - Nelennil.
They entered. - Nelennir.

For verb roots ending in F, the F becomes (-m) for third person singular and (-mi-) for the rest.
Example: For the verb root (laf-):
He or she licked. - E lam.
I licked. - Lemin.
We licked. - Lemim.
You licked. - Lemich.
You licked. - Lemil.
They licked. - Lemir.

For verb roots ending in G, the G becomes (-nc) for third person singular and (-ngi-) for the rest.
Example: From the verb root (nag-):
He or she bit. - E nanc.
I bit. - Nengin.
We bit. - Nengim.
You bit. - Nengich.
You bit. - Nengil.
They bit. - Negnir.

For verb roots ending in L, the L becomes (-ll) for third person singular and (-lli-) for the rest.
Example: From the verb root (tol-):
He or she came. - E toll.
I came. - Tellin.
We came. - Tellim.
You came. - Tellich.
You came. - Tellil.
They came. - Tellir.

For verb roots ending in N, the N becomes (-nn) for third person singular and (-nni-) for the rest.
Example: From the verb root (Than-):
He or she set fire to a branch. - E thann an ngolf.
I set fire to a branch. - Thennin an ngolf.
We set fire to a branch. - Thennim an ngolf.
You set fire to a branch. - Thennich an ngolf.
You set fire to a branch. - Thennil an ngolf.
They set fire to a branch. - Thennir an ngolf.

For verb roots ending in R, the R becomes (-rn) for third person singular and (-rni-) for the rest.
Example: From the verb root (tir-):
He or she watched. - E tirn.
I watched. - Tirnin.
We watched. - Tirnim.
You watched. - Tirnich.
You watched. - Tirnil.
They watched. - Tirnir.

Homework

Symbols that you may need:
áéíóúý
ÁÉÍÓÚÝ
âêîôûŷ
ÂÊÎÔÛŶ

Wordbank

Verbs:
Cen- (see)
Daf- (sit)
Gwedh- (bind)
Dag- (slay)
Ped- (say/speak)
Pel- (whither)
Rhib- (scratch)
Telia- (play)
Tinna- (glint)
Yr- (run)

Adverb:
There (ennas)

Adjectives:
Doll (obscure)

Nouns:
Aran (king)
Hên (child)
Tham (hall)
Merilin (nightingale)
Tinu (star)
Uial (twilight)
Herdir (master)
Orn (tree)

Conjugate all of the verbs in the word bank into past tense.

Cen - cennin / cennim / cennich / cennil / cenn / cennir
Daf - demin / demim / demich / demil / dam / demir
Gwedh - gwennin / gwennim / gwennich / gwennil / gwenn / gwennir
Dag - dengin / dengim / dengich / dengil / danc / dengir
Ped - pennin / pennim / pennich / pennil / penn / pennir
Pel - pellin / pellim / pellich / pellil / pell / pellir
Rhib - rhimmin / rhimmim / rhimmich / rhimmil / rhimb / rhimmir
Telia - teliannen / teliannem / teliannech / teliannel / teliant / telianner
Tinna - tinnen / tinnem / tinnech / tinnel / tinnant / tinner
Yr - yrnin / yrnim / yrnich / yrnil / yrn / yrnir

Translate the following sentences into Sindarin.

We saw that all the king's children played in his master's halls when the stars glinted in the twilight. - Cennim i aran hénath telianner mi thaim herdir dîn ir i thinu tinner ned i uial.
(Informal) I bound you to the tree, and there you sat. - Gen gwennin anin orn a demich ennas.
A nightingale scratched me and ran to the hall. - Merilin nin rhimp ar yrn anin tham.

Translate the following sentences into English.

I cherdir danc lebenchaer verilin i pell ned uial. - The master slew seventeen nightingales that withered in the twilight.
Hên pent enni oh aran noll. - A child spoke to me of an obscure king.
Cennin i verilin i teliant min orn. - I saw the nightingale that played in the tree.