—Have you ___ your father to give up smoking ? —No. I _____ .  but he wouldn’t listen .

 Frequently, single—parent children       some of the function that the absent adult in the house would have served . 

With the word “ PM2.5” ________ appearing in media reports, people pay greater attention to it and seek health tips for smoggy days.

Living with a host family while studying abroad, in which there may be some other college students, __________ you the chance to learn more about the new culture.

(2013·浙江，9)When the group discussion is nearing its end，make sure to ________ it with important points.