Can someone give me some singular to plural and plural to singular basic sentences that are both masculine and female for me to try?

I can only do really basic sentences like:

The boys are slaves.
The boys are roman
The girls are in the fields
Marcus and Sextus are happy.

Really basic stuff.

It would help me to know what textbook you are using, and which edition. Then let me know what your most recent lesson or chapter assignment is.

You have written these; change them into singular forms and let me know how you do:

Pueri servi sunt.
Pueri sunt Romani.
Puellae in agris sunt.
Marcus et Sextus sunt fortunati.

Its ecce roman 1

Puer servus est.
Puer est Romanus.
Puella in agris est.
Marcus est fortunatus.

Those are fine.

http://www.phschool.com/webcodes10/index.cfm?fuseaction=home.gotoWebCode&wcprefix=jfk&wcsuffix=1000
Is this your text? What lessons have you completed?

I aced this test!

Sure, here are some basic sentences for you to practice singular to plural and plural to singular conversions:

Masculine Plural to Singular:
1. The boy is a student. (Change "The boys" to "The boy")
2. The dogs are barking. (Change "The dogs" to "The dog")
3. The men are working. (Change "The men" to "The man")
4. The fathers are proud. (Change "The fathers" to "The father")

Masculine Singular to Plural:
1. The teacher is helpful. (Change "The teacher" to "The teachers")
2. The cat is sleeping. (Change "The cat" to "The cats")
3. The man is driving. (Change "The man" to "The men")
4. The brother is tall. (Change "The brother" to "The brothers")

Feminine Plural to Singular:
1. The girls are dancing. (Change "The girls" to "The girl")
2. The women are talking. (Change "The women" to "The woman")
3. The queens are ruling. (Change "The queens" to "The queen")
4. The sisters are playing. (Change "The sisters" to "The sister")

Feminine Singular to Plural:
1. The nurse is caring. (Change "The nurse" to "The nurses")
2. The woman is reading. (Change "The woman" to "The women")
3. The princess is graceful. (Change "The princess" to "The princesses")
4. The mother is cooking. (Change "The mother" to "The mothers")

Remember, when converting from singular to plural, you generally add an "s" or "es" at the end of the word. And when converting from plural to singular, you remove the "s" or "es" at the end of the word.