"Spotted these people dancing zumba" is not correct grammar but the correct grammar is "I saw these people dancing Zumba"
"Not enough want to change their self," is not correct grammar. You might say that "not enough people wish to make changes in themselves."
It depends on context. For example, in a conversation between two people: Person #1: Those items are not for sale. Person #2: Which are? In that context, it is understood that "Which are?" means "Which items are for sale?"
Yes, "several people" is correct grammar. "Several" is an adjective that can be used to show an unspecified small number of people.
Grammar is tricky. If you did not learn it as a child, the best way to learn it (and know whether your grammar is correct) is to find someone who speaks correct grammar and listen to them, a lot. NPR is a good place to listen to people who have good grammar.
Yes, that is correct.
Beat people up is correct in informal speech. Formally, the verb is simply "beat."
Correct grammar is Bob and I but most people use causal grammer and you and Bob is OK.
Use "people who."
Not at allAnother answer:If you mean 'Is the clause "you were" correct grammar?' the answer is 'yes'.If you mean 'Is the clause "is you were" correct grammar?' the answer is 'no'.If you had taken the trouble to write your question more clearly, you would have helped the people who you hoped would be helping you. Isn't that worth doing?
"Both of whom" is correct grammar. It is used when referring to two people. For example, "I invited John and Mary, both of whom attended the party."
It taught people correct grammar.
It can be correct when used correctly. I am a student of the English language, as are you.