set up & set up relevant&relating am&was

fht99

Which phrase(s) is right?
Set up a new business
Set up in a new business
Set up new business
Set up in new business

I’d like to conduct some relevant investigations.
I’d like to conduct some relating investigations.

When I am writing a letter to a friend, I want to say “I am happy to receive your last letter”
Is it right? Or I have to say “ I was happy to receive your last letter”

your reply and explanation would be highly appreciated!

eriks

I think these two look correct grammatically.

Set up a new business
I was happy to receive your last letter.

I can't explain why but I know the word 'relevent' is correct in such a context.
I’d like to conduct some relevant investigations.

black_zerg

找个native问问

yearshappy

question for the first one
two set up ? or set up & set up in?

set up a new business sounds right

yearshappy

relating to go together
relevant is adjective in this case.
relevant investigations would make sense.

black_zerg

我觉得relevant 听的别扭，related比较顺。我是菜鸟，得请高手指点。