[RonBee]

Originally Posted by bmo

1. (As) sick as a dog.
Very sick.

Example: “Linda, Brian is on the phone, he is asking if you are going to the Sunday school?” “Mom, please tell him it is something I ate at the party last night; I am sick as a dog, I can’t make it.”

Do I need a "the" in front of Sunday school? Should "Sunday" be capitalized? Anything else wrong?

No, you don't need the in fromt of Sunday school. Yes, "Sunday" should indeed be capitalized. (So should Monday, Tuesday, etc.)

Originally Posted by bmo

2. A man is known by the company he keeps.
By looking at your associates, people can tell what kind of person you are.

Example: I am worried about my son. He hangs around with these people with long hair, tattoos in arms and chest, holes in pants, some wearing nose, tongue, and lip rings. A man is known by the company he keeps; I wish he would associate with well-dressed, mannered, and church-going people.

Say: "tattoos on their arms". What's the question?

:)

Originally Posted by bmo

3. (Buying) a pig in a poke
Buying something without first checking it out can bring a surprise.

Example: I am glad the old fashioned, arranged marriages of our great-grandparent’s generation are over. Without seeing each other until the wedding day, how would they know the person they were marrying did not have two noses? It was like buying a pig in a poke – it could be full of surprises.

Should grandparent be plural and anything else wrong?

I would make "grandparent" plural in that sentence. Thus it would be: "our great-grandparents' generation".

:)