Provide SML statement to achieve the following, val t $=(1,[[2],[3,5],[7]])$; $(1)$ Form $4$ from t without using $1$

$(2)$ Form $[5\mathrm{.}0]$ from t

$(3)$ Form $[[7],$ nil, $[1]]$ from t without using $[]$

$(4)$ Form $[(1,2)]$ from t

$(5)$ Form $[$~$1\mathrm{.}5]$ from t