1. This is the most memorable trip I have ever taken.

I've never taken such a memorable trip before

2. I have never talked to any more interesting man than him

He is the most interesting man I have ever talked to

3.No one is as hard-working as my mother.
- My mother is one the most hard-working 

4. There is no harder worker in this factory than John.
→ John is the most hard worrker in this factory.

5.She can sing much more beautifully than me.
→ I can’t sing as beautiful as her.