A.Vietnam exports a lot of rice which grown mainly in the south of the country.
B.Vietnam exports a lot of rice, that is mainly grown in the south of the country.
C.Vietnam, which is grown mainly in the south of the country, exports a lot of rice.
D.Vietnam exports a lot of rice grown mainly in the south of the country.

A.The fire is thought to have been started on purpose.
B.They think that the fire which was started by someone on purpose.
C.The fire is thought to be started on purpose.
D.Someone is thought to start the fire on purpose.

A.The fire is thought to have been started on purpose.
B.They think that the fire which was started by someone on purpose.
C.The fire is thought to be started on purpose.
D.Someone is thought to start the fire on purpose.

A.about
B.where  
C.were  
D.the town

A.students
B.school  
C.to make  
D.friends

A.generating
B.to control flooding  
C.irrigation  
D.surrounding area

A.widely
B.overseas  
C.secretly  
D.alone

A.widely
B.overseas  
C.secretly  
D.alone

A.easily annoyed or irritated
B.feeling embarrassed
C.talking too much  
D.very happy and satisfied

A.round
B.touch  
C.ground  
D.shout