Hi teachers,about underlines of the following sentenes,which one of them is correct?If all are correct,do they have similar meaning?what 's the difference and which one is normally used?Thanks a billion in advance.
These are both 'future' forms, and can often mean the same thing. The 'be to' form states the speaker's belief in a future fact, usually based on some authoritative announcement. The 'be going to' form-- much the commoner form-- is used when the speaker has internal or external evidence of the future event. These descriptions are rather general in application, and overlap considerably. I would think that the most important difference is that the 'be to' form is quite formal and seldom met with.