1. describe 

2. Unfortunately

3. competitors

4. mountainous

III. 

1. My sons like the cakes which are made from cheese

2. ... he would leave here the following day

3. This song has sung by them for the first time

4. VN is a country exporting a lot of rice

I,

1, describe

2, Unfortunately

3, competition

4, mountain

II,

1, The Brown family is traveling in a bus from the airport.

2, Getting some knowledge of first-aid is very important.

III,

1, My son likes the cakes which are made from cheese.

2, He said that he would leave there the next day.

3, This song has not been sung before.

4, Viet Nam is a rice exporter country.

             Good luck!!!