1) a deal = 一个交易; "Japan has done a deal with America on car exports."
2) Many deals =复数:They had to make some deals to get the bill passed.International buyers typically look at deals valued at a minimum of $5 million.
3) a great deal of :They made a good deal of noise.She spent a great deal of money on it.大量
4) "a deal of"; "many deals of" =少见!