Explanation:
48: Nick is a careful write than Phuc.
Nick writes essays carefully.
49: A snail is slower than a scrab.
A snail moves slowly.
50: My father's explanatoon about the subject was clearer than my brother's.
My father explained the subject clearly.
51: My ciuser is a better singer than I am.
My cousin sings well.
52: Phong is a faster swimmer than Phuc.
Phong swims fast.