`a.` The Nile is the longest river in the world.

`b.` Lan is the tallest student in my class.

`c.` English coffee is the worst of all.

`d.` Australia is the smallest continent in the world.

`e.` That is the highest mountain in the world.

`*` Kiến thức :   So sánh nhất : S + tobe + the adj-est/most adj + ..... 

=>

a. The Nile is the longest river in the world.

b. Lan is the tallest student in my class.

c. English coffee is the worst of all.

d. Australia is the smallest continent in the world.

e. That is the highest mountain in the world.

So sánh nhất:

Tính từ ngắn: the adj-est

Tính từ dài: the most adj

So sánh nhất của bad là the worst