Cars do cause us some health problems—in fact far more serious ________ than mobile phones do.
Although _____of danger, tourists can't help taking photos near the cliff (悬崖) .
We're considering students' request ______the school cafeteria should provide more kinds of food.
—Oh, doctor, The wound on my leg is infected. —You really shouldn’t have left it _______ to the sun.
____ you call me to say you are not coming, I will see you at the theatre at five this afternoon.
—Would you rather come on Friday or Saturday?—________________.