من الضروري أن تكون المرافق والأثاث في حالة جيدة.

Literally, من الضروري is something like from the necessary, but as a fixed expression it means it is necessary.

Arabic often uses من + a definite adjective/noun in impersonal expressions:

• من المهم = it is important
• من الأفضل = it is better
• من الضروري = it is necessary

So you should learn من الضروري as one common phrase.

أن introduces a following clause, much like English that in it is necessary that...

So:

• من الضروري = it is necessary
• أن تكون... = that ... be

Also, أن affects the verb after it and puts it in the subjunctive mood.

تكون is from the verb كان, which means to be.

Here it is the imperfect form used after أن, so the full vowelled form is تكونَ. In normal unvowelled writing, you just see تكون, so the subjunctive ending is not visible.

So the structure is:

• أن تكون = that it be / that they be

A big reason is that المرافق is a non-human plural, and in Arabic, non-human plurals are often treated like feminine singular for agreement.

So even though المرافق means facilities, Arabic often agrees with it as feminine singular:

• المرافق جيدة
• كانت المرافق...
• أن تكون المرافق...

Also, because the verb comes before the subject, Arabic normally does not use full plural agreement there.

That is a very common question.

In a simple sentence, Arabic would usually say:

• المرافق والأثاث في حالة جيدة
• literally: the facilities and the furniture in good condition

There is no written are there.

But after أن, Arabic commonly uses تكون to express that ... be:

• من الضروري أن تكون المرافق والأثاث في حالة جيدة

So the verb appears because of the clause structure, not because Arabic suddenly always needs a present-tense to be.

المرافق is the plural of مرفق.

Depending on context, it can mean:

• facilities
• amenities
• services
• building facilities

In this sentence, facilities is the most natural translation.

Grammatically, الأثاث is usually treated as a singular collective noun, even though it refers to many items.

It works a lot like English furniture:

• English: furniture is grammatically singular
• Arabic: الأثاث is also treated as a singular noun

If you want to refer to one item, you would usually say:

• قطعة أثاث = a piece of furniture

Literally, it means in a good condition or in a good state.

This is a very common Arabic expression for saying something is in good condition:

• في حالة جيدة = in good condition

It is more idiomatic than simply saying the facilities and furniture are good. It specifically refers to their condition or state.

جيدة describes حالة, not المرافق or الأثاث.

So the internal structure is:

• في حالة جيدة
• in a good condition

Because حالة is feminine singular, the adjective is also feminine singular:

• حالة جيدة

This is why جيدة is not matching المرافق directly.

Because the sentence is speaking generally: in good condition, not in the good condition.

Using حالة without الـ keeps the meaning general and idiomatic. If you said في الحالة الجيدة, it would sound like you were referring to one specific previously known condition, which is not the idea here.

Yes. بحالة جيدة is also common and natural.

Both can mean in good condition:

• في حالة جيدة
• بحالة جيدة

In many contexts they are interchangeable. في حالة جيدة can sound a bit more formal or standard in written Arabic, but both are correct.

They are close, but not exactly the same in tone.

• من الضروري أن... = it is necessary that...
• يجب أن... = must / has to / should

من الضروري أن... sounds a bit more impersonal and formal.
يجب أن... sounds more direct and stronger.

So in many situations both are possible, but the tone changes slightly.