Question

1. How many rowers are there on a team?
2. How many rowers are there in a team?

3. I'm actually on the school badminton team.
4. I'm actually in the school badminton team.

(Which preposition do we have to use?)

5. Everyone is doing very well.
6. Everyone is going greatly.
7. Everyone is doing great.

(Which ones are grammatical?)

Answer 1

"on" is usually used when referring to being on a team.

#5 is the grammatically correct sentence, even though #7 is used in casual speech. #6 is not used.

Answer 2

Thank you for your help. There was an error in the previous sentence. What about #6 below?

5. Everyone is doing very well.
6. Everyone is doing greatly.
7. Everyone is doing great.

Answer 3

#6 is not used in normal English speech. The word "greatly" is an adverb, but is not normally used in this way. Here is a sentence that shows how to use "greatly" --

Her help was greatly appreciated.

It's best used as an adverb modifying an adjective, not modifying a verb. I know it's odd, but ... that's English!