Which one is correct?Help

[richard001]

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.

This is the first step to do it.

This is the first step of doing it.

This is the first step for doing it.

[Mister Micawber]

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I like #3 best; the other two sound unnatural to me. I would also say, 'in doing it' and even 'to doing it'-- the 'to' is not part of an infinitive verb form, it means 'toward'.

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[richard001]

I get it with your help,thank you.

Can you help me further for telling what difference is between the two below?

He is to go to New York next week.

He is going to New York next week.

[Mister Micawber]

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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.

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