Sorry, I try to use the grammatical terms as much as possible because they are the shortest way to express the concept (expecting the reader to look up what the terms mean
).
The indefinite article we both marked as wrong-
uno-precedes a noun, and it must agree with that noun in gender and number. The word '
razón' is a
singular,
feminine noun, so you have to choose the singular feminine indefinite article '
una' (I suggest you memorize all nouns with their articles, both singular and plural). If the feminine noun is plural, you use 'unas'. If the noun is masculine, the singular indefinite article is '
un' and the plural is '
unos'.
There are definite articles, too. They are '
la', '
las', '
el' and '
los', respectively.
You most likely recognize the term 'present tense'. That is used to describe verbs whose action is happening now, in the present. The 'indicative' part names the mood. Spanish cares a great deal about the mood. It is 'indicative' if it is real or factual. It is 'subjunctive' if it is not real or factual, including events that haven't transpired yet. The 'imperative' mood is used to give a command. The 'conditional' mood is self-explanatory (yay!).
All things grammar are somewhat spelled out in the
Grammar section, if you want to take a gander. Idiomatic expressions, like the one just used, can be found in the
Idioms section. Search on 'gander' to see what the expression is in Spanish.