(1)A ten feet long snake made people run here and there
(2)We are going to the concert, and so they are.
(3) Enclosed with this letter was a signed Affidavit and a carbon copy of his
request to our main office.
(4) Fear from God.
(5) Pakistan has and will support the Kashmiris.
(6) He has come yesterday.
(7) Arshad's down fall was due to nothing else than pride.
(8) Do not avoid to consult a doctor.

(1)A ten feet long snake made people run here and there
I think the correction required here is related to redundancy. 'Ten feet' already says everything that 'ten feet long' says. So the right sentence would be
A ten feet snake made the people run here and there.

(2)We are going to the concert, and so they are.
We are going to the concert and so are they. OR . We are going to the concert, and so are they.
(3) Enclosed with this letter was a signed Affidavit and a carbon copy of his
request to our main office.
Verbal phrase issue: We dont say 'Enclosed with' - 'Enclosed in' or 'Enclosed with in' is right. Also, the A of Affidavit should be a small lettered a for affidavit is not proper noun. Enclosed with in this letter were a signed affidavit and a carbon copy of his request to our main office. [The noun is plural so we use were]
(4) Fear from God.
Fear of God.
(5) Pakistan has and will support the Kashmiris.
Pakistan has supported and will support the Kashmiris.
(6) He has come yesterday.
He came yesterday
(7) Arshad's down fall was due to nothing else than pride.
Arshad's down fall was due to nothing else but pride.
(8) Do not avoid to consult a doctor.
I would put this sentence like 'Do not avoid consulting a doctor'. 'Avoid to' is not the right expression.

Suggestions and corrections will be appreciated.

In the last sentence,if we use "to consult" rather than "consulting" how this will change meaning?
i have read to+ verb base= verb participle; means "to consult"= "consulting" , then how will it have changed the meaning in the sentence were corrected by you?

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SHAH