Note that gustar is not reflexive, you well pretty much never see "se gusta" in the wild.
The subject of a gustar sentence doesn't need to have a definite article. In general, you use the definite article for a subject when you're making a general statement, meaning you're claiming that something applies to every instance of that subject:
- Me gusta el café. - I like coffee. Whenever there's coffee, I like it.
- Las vacas dan leche. - Cows give milk. Whenever there's a cow, it gives milk.
- Los peces huelen mal. - Fish smell bad.
But if you're not making a generalisation or talking about a specific subject (which would use "the" in English), then you're not going to use a definite article in the Spanish sentence:
- Me gusta una de estas niñas. - I like one of these girls.
The other thing you have to note is that gustar has a verbal subject in the above sentence: it's not the food that you like, it's eating the food. Verbal subjects don't usually get articles.
- Me gusta leer. - I like to read.
- Me gusta leer libros. - I like to read books.
- Me gusta leer el libro. - I like to read the book.
Often on web version of the app the audio is being cut and here i have heard only "me gusta comer arroz" - marked wrong obviously... Weird thing is that it is often cut in such important places - like missing final "por favor" or "grazias".. like someone was doing it on purpose ;P
Just the way gustar works. Think of it as "rice pleases me" or "rice is pleasing to me"--conjugate gustar to go with rice/it gusta as the subject (not yo) and then the "me" for the object. If you like rice, it's the same way with you as the object--"te (not tú) gusta arroz." If you like something plural, you change the gustar conjugation: I like eggs--me gustan huevos (eggs please me).
Frijoles = beans. It doesn't mean just one certain type of beans. For example my family calls red beans, frijoles. Green beans = frijoles verdes or judias verdes (according to Google Translate, Spanishdict, Linguee, Collins Dictionary, and Word Hippo). Growing up, we called it frijoles verdes when we're referring to green beans.