After a year, doctors diagnosed him with a disease so rare ________ it affects just one in 8 million children.
How can they learn much ________ they spend so much time playing computer games?
Cars do cause us some health problems, in fact, far more serious ________ than mobile phones do.
After ________, the litter girl was depressed and kept silent all the day.
The scientist corresponds with colleagues in order to learn about matters ________ to her own research.
Chinese folk music gave ________ life to Mr Liu and made him lead ________ new life in his later years.