Ответ: Askar and I are going to run a marathon for charity next month.We hope than all our friends will sponsor us, so we will make a lot of money.

I think that the biggest problem will be getting fit. That's why we are going to start training soon. Askar says he is going to run 10 kilometres before school every day. But I don't think he will train every day because he hates getting up early.

Объяснение:

Future Simple употребляется,когда речь идёт о:

- сиюминутных решениях: I like this shoes.I will buy them

- прогнозах и предсказаниях на будущее обычно с выражениями:

I think, I hope, I believe, I expect  с наречиями probably и perhaps: I think they will be able to solve the problem. Perhaps Frank will change his mind about it.

- об обещаниях ( обычно с глаголами promise/swear и т.д) : I promise i will take you to the museum tommorow.

- об угрозах : Lie to me again ant it will be the end of our friendship.

- об предупреждениях: Drive more carefully or you will have an accident.

- o надежде: He hopes they will choose him for the job.

- о предложениях: I will make you some coffee.

- об информации о будущем действии : It will be spring soon.

Be going to употребляется, когда речь идёт о:

- планах на будущее и намерениях: Paul is going to travel abroad next mounth. ( He is planning to...)

- прогнозах,основанных на том,что мы видим или знаем: Look out! You are going to fall into the pool.

- принятых решениях по поводу действий в ближайшем будущем: Sally is going to look for a new job. ( She has already decided to do this)