megane wo kakereba, kokuban no zi ga yomemasu.

It is read:

めがね を かければ、こくばん の じ が よめます。

Word by word:

• 眼鏡 = めがね = glasses
• かければ = if someone wears/puts on
• 黒板 = こくばん = blackboard
• 字 = じ = letters/characters/writing
• 読めます = よめます = can read

かければ is the -eba conditional form of かける.

• かける = to put on / wear something like glasses
• かければ = if you wear / if one puts on

So:

• 眼鏡をかければ = if you wear glasses

This kind of conditional often sounds a bit like a logical condition: if X, then Y.

Japanese uses different verbs for wearing depending on the item.

For example:

• 着る for clothes on your upper body
• はく for shoes, pants, skirts
• かぶる for hats
• かける for glasses

So 眼鏡をかける is the normal expression for to wear glasses.

Even though English uses one verb, wear, Japanese splits this idea into several verbs.

Because 眼鏡 is the thing being put on, so it takes を with かける.

• 眼鏡をかける = to wear/put on glasses

Here, を marks the direct object of the verb かける.

So the structure is:

• 眼鏡をかける = wear glasses
• 眼鏡をかければ = if you wear glasses

Because 読めます is the potential form of 読む.

• 読む = to read
• 読める / 読めます = can read / be able to read

So:

• 字を読みます = read the writing
• 字が読めます = can read the writing

With potential verbs in Japanese, the thing that can be done is very often marked with が.

That is why 字が読めます sounds natural here.

With potential forms like 読める, 食べられる, 見える, and so on, Japanese often marks the object with が rather than を.

So:

• 日本語が話せます = can speak Japanese
• 漢字が読めます = can read kanji
• 黒板の字が読めます = can read the writing on the blackboard

A simple way to think about it is that が marks the thing that is possible/able to be done.

Learners should know that object marking with potential forms can be a bigger topic, but for this sentence, 字が読めます is standard and natural.

黒板の字 literally means the blackboard’s letters/characters, but in natural English it means:

• the writing on the blackboard
• the letters on the blackboard

Here, の connects two nouns:

• 黒板 = blackboard
• 字 = writing/characters/letters

So A の B does not always mean strict possession. It can also mean B related to A, B on A, B belonging to A, and so on.

In this sentence, 黒板の字 means the writing that is on the blackboard.

字 often refers to characters, handwriting, or written marks, and in everyday sentences like this it naturally means the writing.

So 黒板の字 sounds like:

• the writing on the blackboard
• what is written on the blackboard

文字 is also a real word, but it often sounds a bit more like characters/letters as a category. In this sentence, 字 is the more natural choice.

Japanese often leaves the subject unstated when it is clear from context.

So this sentence could mean:

• If I wear glasses, I can read the writing on the blackboard.
• If you wear glasses, you can read the writing on the blackboard.
• If he/she wears glasses, he/she can read the writing on the blackboard.

The exact subject depends on the situation.

This is very normal in Japanese. You usually do not need to say 私 or あなた unless it is necessary for clarity or emphasis.

Both can mean if you wear glasses, but the nuance is a little different.

• かければ often sounds more like a general or logical condition
• かけたら often sounds more conversational and situation-based

So:

• 眼鏡をかければ、黒板の字が読めます。

  • If I wear glasses, I can read the writing on the blackboard.
  • Slightly more matter-of-fact or explanatory

• 眼鏡をかけたら、黒板の字が読めます。

  • Also very natural
  • A bit more like when/if I put on my glasses

In many everyday contexts, both are possible.

Yes. メガネ and 眼鏡 are the same word.

In modern everyday writing, メガネ is very common because it is easier to read quickly.
眼鏡 is the kanji version and is also correct.

So these are both fine:

• 眼鏡をかければ、黒板の字が読めます。
• メガネをかければ、黒板の字が読めます。

Because 見える and 読める are related but different.

• 見える = to be visible / can see
• 読める = can read

If something is far away, you might be able to see that there is writing, but not be able to read it.
This sentence specifically says that with glasses, the person can actually understand the characters on the blackboard.

So:

• 黒板の字が見えます = I can see the writing
• 黒板の字が読めます = I can read the writing

It can be understood either way, depending on context, but it often sounds like a practical/general statement:

• If I wear glasses, I can read the writing on the blackboard.

That could describe:

• a general fact about someone's eyesight
• the situation in a classroom right now

Because Japanese often relies on context, the sentence itself does not force just one interpretation.