Today we feel proud __________ our school.
_______ his scientific work, he has no time to care for his family affairs, _______, of course, his wife always complains about.
The silence in the dark building was scaring. No sound and voice____ heard at that moment.
If _____ without following the doctor’s instructions, the medicine may have serious side effects.
________ you happen to see Mary, would you please ask her to come here?
Everyone knows that _______ is dangerous to play with fire, but _______ is difficult is to prevent children from playing with fire.