"Le" means "The", while "Du" is "Some (of the)"
So, "Je mange le pain" means you are eating THE bread, or a specific bread. Where as "Je mange du pain" means you are eating some bread or bread in general.
For example, in English when you are hungry for bread, you don't say "Man, I am really hungry. I want to eat the bread." You say "I want to eat some bread".
Hope this makes sense!
Please have a look at the following link:
French articles agree with the nouns they modify.
In French, there is always an article in front of a noun, unless you use another type of determiner , for example:
- a possessive adjective (mon, ton, etc.)
- a demonstrative adjective (ce, cette, etc).
There are conjugation forms for each verb. When you want to know how to conjugate a verb, hover your mouse over it: click on the "conjugate " option, and you'll get a conjugation table.
Please also have a look at this comment:
French verbs are conventionally divided into three conjugations ("conjugaisons").
The first two groups follow a regular conjugation, whereas the third group follows an irregular one.
1st GROUP : verbs ending in "-er" (except aller).
- ex: "manger" (to eat) : Je mange (I eat); Tu manges (you eat); Il/Elle mange (he/she eats); Nous mangeons (we eat); Vous mangez (you eat); Ils/Elles mangent (they eat).