Viết lại câu sao cho nghĩa không thay đổi

Viết lại câu sao cho nghĩa không thay đổi:
1. This exercise is easier than that one
->That exercise...........
2. His father drives more carefully than Chris does.
-> Chris...........
3. Your mother is more kind-hearted than enyone.
-> There isn't anybody..............
4. Lily's mother was generous than her.
-> Lily................