מסגרת המשקפיים יושבת נכון בלי שהאפון זז.

Because the sentence is talking about the frame of the glasses, not about multiple frames.

• מסגרת = frame
• משקפיים = glasses

So מסגרת המשקפיים literally means the frame of the glasses.

Also, משקפיים is one of those Hebrew nouns that looks plural and behaves grammatically as plural, even though in English we often treat glasses as a single item in meaning.

This is because of construct state (called סמיכות in Hebrew).

In a construct chain like:

• מסגרת המשקפיים

the first noun usually does not take ה־, and the definiteness is shown on the second noun:

• מסגרת המשקפיים = the frame of the glasses
• not usually המסגרת של המשקפיים in this compact style

Since המשקפיים is definite, the whole phrase becomes definite.

Because the subject is מסגרת, and מסגרת is a feminine singular noun.

So the verb in the present tense agrees with it:

• מסגרת ... יושבת
• if the subject were masculine singular, you would expect יושב

Even though משקפיים is plural, it is not the grammatical head of the phrase here. The real subject is מסגרת.

Yes, literally יושבת means sits / is sitting, but in Hebrew it is very common to use יושב / יושבת for how something sits, rests, or fits on something.

So with clothing, glasses, a hat, a frame, etc., Hebrew often uses this verb where English might say:

• fits well
• sits properly
• is positioned correctly

So מסגרת המשקפיים יושבת נכון is very natural Hebrew for saying the frame is sitting/fitting correctly.

Because נכון here is being used adverbially, meaning something like correctly or properly, not as an adjective directly describing מסגרת.

In Hebrew, the masculine singular form of an adjective is often used as an adverb:

• הוא מדבר ברור = he speaks clearly
• זה עובד טוב = it works well
• יושבת נכון = sits/fits correctly

If it were directly describing the noun מסגרת, then you would expect feminine agreement, like מסגרת נכונה, but that is not what is happening here.

בלי ש־ means without ..., followed by a full clause.

So:

• בלי = without
• ש־ = that / introducing a subordinate clause

In this sentence:

• בלי שהאפון זז

literally = without the nose pad moving

Hebrew often uses בלי ש־ when there is a separate subject in the without clause.

Because בלי לזוז means simply without moving, but it does not clearly state what is not moving.

Here the speaker specifically wants to say that the nose pad is not moving, so Hebrew uses a full clause:

• בלי שהאפון זז = without the nose pad moving

If you said בלי לזוז, it might sound like the thing not moving is the frame itself, or it could be vague.

So בלי ש־ + subject + verb is useful when you want to name the subject clearly.

Because האפון is masculine singular.

So the present-tense form must agree with האפון:

• masculine singular: זז
• feminine singular: זזה

That means:

• האפון זז = the nose pad moves / is moving

If the subject were המסגרת, then you would say:

• המסגרת זזה

Yes — in everyday Hebrew, אפון usually means pea.

But in the context of glasses, אפון can also mean the little nose pad on the frame. This is a specialized usage.

So in this sentence, האפון is not a vegetable — it means the small part of the glasses that rests near the nose.

This is exactly the kind of vocabulary that can confuse learners, because the common meaning and the technical meaning are very different.

Yes.

• יושבת = present tense
• זז = present tense

Hebrew present-tense forms often look like participles in English grammar descriptions, but in normal usage they function as the everyday present tense.

So the sentence describes a current state:

• the frame sits correctly
• the nose pad is not moving

Yes, very possibly, depending on nuance.

• יושבת טוב = sits/fits well
• יושבת נכון = sits/fits correctly

The difference is small but real:

• טוב focuses more on well
• נכון focuses more on correctly / properly

In technical, fitting, or instructional contexts, נכון can sound more precise.