---Oh dear, why are you killing time this way? ---I can’t find anything worth ___________.
I ________ with my grandma because my parents have gone abroad for further study.
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.