1．Why do_you_think some adolescents start smoking?
你认为有些青少年为什么会开始吸烟？
do you think 在句中做插入语。这种句式也可叫做双重疑问句。其构成有两种情况：
(1)做主语的疑问词＋do you think/suppose/believe/imagine/say/suggest＋谓语部分？
(2)非主语的疑问词＋do you think/suppose/believe/imagine/say/suggest＋主语＋谓语部分？
①Which film do you think will win the Golden Lion of the 66th Venice International Film Festival？你认为哪一部电影会赢得66届威尼斯国际电影节金狮奖？
