1.Nick is a carefu writer than Phuc(carefully)

=>Nick writes esays MORE CAREFULLY THAN PHUC DOES.

2.A snail is slower than a crab(slowly)

=>A snail moves MORE SLOWLY THAN A CRAB.

3.My father's explanation about the subject was clearer than my brother's(clearly)

=>My father expleined the subject MORE CLEARLY THAN MY BROTHER DOES.

4.My cousin is a better singer than I am(well)

=>My cousin sings BETTER THAN I DO.

5.Phong is a faster swimming than Phuc(fast)

=>Phong swims FASTER THAN PHUC DOES.