"I will be eating the sandwich."

Translation: Εγώ θα τρώω το σάντουιτς.

[dillesuzbruk]

Isnt το σάντουιτς supposed to be ο σάντουιτς? Because I thought if the ending of the word is ς, then the word is masculine, not neuter.

[D_..]

Σάντουιτς is neuter, therefore goes with το. It's a loanword, so its ending is irrelevant for the grammatical gender. In fact, words ending in -ς, while mostly masculine (δρόμος=road, επαρκής=sufficient), can also be feminine (οδός=street, επαρκής) or neuter (δάσος=forest, επαρκές).

[KeithJones949537]

is it not allowed to miss out the definite or indefinite article? I thought I had seen this happen in the last question.

[troll1995]

Missing the definite article would result to indefinite.

[KeithJones949537]

got it! thank you

[jaye16]

Not in Eng. You would need either "a" or "the".

[mmerida]

Why θα before eating? does it represent the future?

[jaye16]

Yes, it does but there is no reason at this early stage to go into how to construct the future. This Skill is meant to teach basic phrases; in later Skills you'll get more experience in how they are constructed.