The Conditional なら

Conditionals are a ton of fun in Japanese, because there's at least four different ways of saying "if...", depending on the rest of the sentence and context. No, I'm not putting off this lesson by complaining about painful grammar points.

なら is sometimes referred to as a "contextual conditional", describing something within a given context. The format of a sentence is often "Topic A なら predicate X", which states that the predicate only applies to A. It sounds something like "In the case of A, then X is true."

I'm going to write out Genki's examples, because I need a bit more research to construct my own.

ブラジルに行ったことがありますか？
Have you ever been to Brazil?

チリなら行ったことがありますが、ブラジルは行ったことがありません。
I've been to Chile, but never to Brazil.

日本語が分かりますか？
Do you understand Japanese?

ひらがななら分かります。
If it's (written) in hiragana, yes.

In the first example, なら is used to show that the "going" action only applies to Chile, not Brazil. In the second, it's providing a limitation, stating that comprehension is only true in the case of hiragana.

The に particle could have been used after チリ in the first example, but it can optionally be dropped. Particles like に, で, and から can be used with なら, while は, ご, and を cannot.