Use a superlative :
Ex : "This exercise is very difficult : it's the most difficult exercise" (I've ever done !)
1- It was a very happy day : it was…………….. in my life.
2- It's a very good book : it is ………………… I've ever read.
3- He's a very famous singer : he's certainly …………….. in the country.
4- I know it was a bad mistake : it was …………… I had ever done.
5- She's a very pretty : she's ……………….of the class.
6- It was a very cold winter : it was …………….. we had ever known.
7- Hamid is a boring man : he's ………………… I've ever met.
8- Dalila is really a funny child : she is ………………. in the family.