用方框中所给短语的适当形式填空

all of a sudden, be ashamed of, be burdened with, be-long to, turn. . . into, in return

 
__________，she burst into laughter.
Chinais a country __________ the third world.
She __________ having failed.
Nowadays, the students __________too much home-work.
Theyare __________ waste land __________ rice fields.
I treated her to dinner __________ for her help.