A subordinate clause is a sentence within a sentence.

"That/Who" for beginning subordinate clauses is (i). In English, we often leave this word out, so be careful.
Example:
I am the girl who saw uncountable orcs. - Ni i 'wenn i tírant veneg yrch.
The wind that blows. - I hûl i hwesta.
You know [that] I wish to remain. - Istach i aníron darthad.

"For he or she who" for beginning subordinate clauses is (anin), and "for those who" for beginning subordinate clauses is (ai).
For he who loves, a flower blossoms. - Anin mela loth edlothia.
Death follows [for] those who stray. - Gurth aphad ai mistar.

"When/while" for beginning subordinate clauses is (ir).
Example: I will go when I have no friends. - Bedithon ir ú-gerin vellon.

"If" for beginning subordinate clauses is (ae).
Example: If you are brave, you will fight. - Ae le beren maethathal.

Homework

Symbols that you may need:
áéíóúý
ÁÉÍÓÚÝ
âêîôûŷ
ÂÊÎÔÛŶ

Wordbank

Verbs:
Ista-knows

Nouns:
Innas-will
Hwann-mushroom
Nen-water
Imlad-valley
Palath-surface
Cuil-life

Adjectives:
Estent-short

Translate the following into Sindarin:
If he touches me, I will know his will. - Ae e nin matha istathon innas dīn.
Drain the water when the mushroom touches its [the water's] surface. - Sautho i nen ir i chwann matha balath dīn.
We know the water that drains in the valley. - Istam i nen i sautha min imlad.

Into English:

Cuil estent anin matha i chwann. - Life is short for she who touches the mushroom.
Cuil ista innasath ai mathar guil. - Life knows all wills for those who touch life.