'The football team is doing well!'
no it is not a correct sentence.
"He is good" is correct. 'He' is singular, 'are' is for plurals.
Always do good is correct and means what it says. "Always be a good doer" means something slightly different from what it says. A good doer is person who is known for doing good, not necessarily a person who does good.
No, Are Jack and Jill good football players is
This sentence is completely correct.
"he is a great chess player" is grammatically correct, but the rest could be better. No one really says footballer, a better choice would be Football player try: "he plays football and chess well." or "he's great at both football and chess."
The person's a criminal for doing what he did.
When a book is good, I get lost. It was this sentence grammatical corrected.
If the person is doing something positive according to their beliefs and morals, they are doing good. If they are doing something properly and correctly, they are doing it well. The distinction is this: doing good means achieving worthwhile ends, especially to society's benefit, while doing well means succeeding, especially at making money. In the first case, "good" is a noun, the direct object of the verb do. In the second, "well" is an adverb modifying the verb do.
Your brother is exceptionally good at football.
"My mathematics is good" is correct out of the choices given, but a better sentence would be "I am good at mathematics".
well it is correct but the grammar is wrong instead say "are you good at swimming" they both mean the same but this sentence a correct pronunciation.No. We say we are good at something if we mean that we do it well. The sentence "You are good in swimming" might be correct, but only if "swimming" is the name of a course of study, just as we might say "You are good in French," meaning you get get high marks in French class.