1.No mountain in Viet Nam is as high as Fansipan

->Fansipan is the highest in Viet Nam

2.The MeKong river is longer than the red river

->The Red river is shorter than The MeKong river

3.It is not good to stay up so late to listen to music

->You shouldn't stay up so late to listen to music.

4.How many times a week do you go to your painting club?

->How often do you go to your paining club?

5.Nobody is older than my grandfather in my family

->My grandfather is the oldest in my family

6.It is essential that you do your homework before going to class

->You must  necessary that you do your homework before going to class

Fansipan is the highest mountain in Vietnam

The Red river is shorter than the Mekong river.

You shouldn't stay up so late to listen to music.

How often do you go to your painting club a week?

My grandfather is the oldest in my family.

You must do your homework before going to class