Different ways of talking or writing about future events in English have different meanings. Here are some examples：
PREDICTING future events：
-It will probably be difficult to get them to pay on time.
-Prices will/are going to go up if the exchange rate changes.
-By this time next year， our costs will have risen by 25%.
-If the exchange rates change， prices will/are sure to rise.
-We'll still be unloading the goods at 3p.m.
-Please don't call after 12：30， Mr. Carter will be having lunch then.
Describing a PLAN or ARRANGEMENTS：
-I'm visiting/I'll be visiting Tokyo in November.
-She's arriving/She'll be arriving this evening.
Saying what you INTEND to do：
-I'm going to chase them up if they haven't delivered by Friday.
-I'm going to have lunch early today.
Making a PROMISE：
-I'll let you know next week.
-I'll make sure Mrs. Hanson calls you back as soon as she's free.
-Mr. Brown will pick you up at the airport.
Referring to FACTS（timetables or schedules）：
-My plane for Buenos Aires leaves at 14：35.
-When do you arrive in Mendoza？
-Next Friday is a public holiday in Argentina.
Talking about something that is going to happen VERY SOON：
-I'm just about to/just going to phone Sydney.
-They're just going to/just about to start the meeting.
It's sometimes more polite to use will be doing：
-When will you be calling Mr. Lee in Singapore？
-Will you be seeing Mr. Kwouk while you're in Hong Kong？
instead of： When will you……？ or Are you going to……？
PREDICTING future events：
-It will probably be difficult to get them to pay on time.
-Prices will/are going to go up if the exchange rate changes.
-By this time next year， our costs will have risen by 25%.
-If the exchange rates change， prices will/are sure to rise.
-We'll still be unloading the goods at 3p.m.
-Please don't call after 12：30， Mr. Carter will be having lunch then.
Describing a PLAN or ARRANGEMENTS：
-I'm visiting/I'll be visiting Tokyo in November.
-She's arriving/She'll be arriving this evening.
Saying what you INTEND to do：
-I'm going to chase them up if they haven't delivered by Friday.
-I'm going to have lunch early today.
Making a PROMISE：
-I'll let you know next week.
-I'll make sure Mrs. Hanson calls you back as soon as she's free.
-Mr. Brown will pick you up at the airport.
Referring to FACTS（timetables or schedules）：
-My plane for Buenos Aires leaves at 14：35.
-When do you arrive in Mendoza？
-Next Friday is a public holiday in Argentina.
Talking about something that is going to happen VERY SOON：
-I'm just about to/just going to phone Sydney.
-They're just going to/just about to start the meeting.
It's sometimes more polite to use will be doing：
-When will you be calling Mr. Lee in Singapore？
-Will you be seeing Mr. Kwouk while you're in Hong Kong？
instead of： When will you……？ or Are you going to……？