根据句意，补全单词。

1.  It's important to______ a healthy lifestyle.

2.  Exercising helps teenagers to______ healthy,

3.  I'd never allow my children to______ like that.

4.  They know it is never too______ to change bad habits.

5.  Wang Le wants to do things that most teenagers______.

从学生的学习过程来看，研究性学习的实施步骤可以表述为（）。 ①作出假设②制定计划③提出问题 ④得出结论⑤表达交流⑥实施计划

A.①③②⑥⑤④

B.①③②⑥④⑤

C.③①②⑥④⑤

D.③①②⑥⑤④