I am expecting somebody can reply my questions,thanks a lot.

When,while and as

a) What are the differences between them,they all mean that during a period and something is happening.

1) We were attacked with rotten eggs by a group of gangsters while/when/as passing by the street.

2) I used to visit my grandfather twice a month while/when/as I was young.

3) He has been there while/when/as we just arrived the airport.

Which preposition are correct for these sentences?

b) Like and as

1)All of us are dressed as/like ghosts and witches to celebrate Halloween in a crazy midnight party.

2)He makes an announcement to employees like/as he is the management director of the company.

Like and as are the same ? However,I consider that as is more formal than like in English.

Thank you in advance.
Please,answer my question~I really need your help.
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"While" focuses on the duration of a process and "as" on the process itself.
Anonymous"While" focuses on the duration of a process and "as" on the process itself.
It does not make sense much to me.Could you explain further in detail ?

Could you give me some examples to let me understand clearly what the difference between 'as' and 'while' is ?

1) I am making my breakfast while/as/when my mum is still sleeping.

2)I am reading newspaper while/as/when I am waiting for a bus.

3)He is going towards the restaurant while/as/when his friend is waving his hand to him.

In your view,what are the correct answers for the questions shown above ?

Seeking your help kindly.
 CalifJim's reply was promoted to an answer.
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