subject
Frequency is a noun.
The word inventions is a noun. It is the plural form of invention.
Depending on whether the air conditioner is a "central operating unit" or if it is a "stand alone unit". The stand alone is an equipment purchase whereas a "central" is now part of the building.
Accessory - It is a necessary things need to work equipment properly or perfectly.Simple example we purchase one pen, it should with pen cap.Think, with out cap off-course we can write.But it is not a perfect pen.So pen cap is an accessory coming with pen. Spare parts- It is some extra part coming with equipment to future use. Example: Pen refill
part of speech
The part of speech for this particular word is a noun.
adverb
what part of speech is work
what part of speech is beneath
the part of speech sashay is a averb
Did is a verb, and not is an adverb. Didn't is not any part of speech. It's a contraction of did and not.
Adjective
The word speech is a noun.
No, but it's part of a noun which the noun is the part of speech.
Yes, conjunction is a part of speech.
What part of speech is thaw