He had little idea that it was getting so late, ___________ ?
—Do you think students’ using mobile phones has any advantages? —______.
Everyone knows that ______ is dangerous to play with fire, but ______ is difficult is to prevent children from playing with fire.
Keep in mind that you should try to spend your time on what you find ______.
Present ______ the ceremony were the honorable heroes, who were presented ______ awards for their good deeds.
Down ran an old man who was ______ convinced of the benefits of running, so he ran everyday.