Heavy schoolbags are causing back problems.It sure is.But we

Heavy schoolbags are causing back problems.It sure is.But we can't decide what to do/how to do it
答案是what to do,但是第二个为什么不对,希望给出具体清楚的解释,

Heavy schoolbags are causing back problems.It sure is.But we can't decide what to do/how to do it
句子意思：沉重书包正在引起/引发后背问题,它是一定的,但是我们不能决定该做些什么去解决这个问题.
We can't decide what to do =We can't decide what we should do (to solve the back problems)
再问： 似乎明白了，可否举些how to do it 的用法例句？谢谢
再答： （1）特殊疑问代词what +动词不定式to do 构成短语表达意思：应该要做些什么事情 特殊疑问代词what 充当不定式动词do 的宾语成分 （2）特殊疑问副词 how +动词不定式to do 构成短语表达意思：应该要要怎么样做一些事情 特殊疑问副词 how 充当不定式动词do 的状语成分 （1）how to do =怎么做 ;如何做，强调做某事的方法，和过程 （2）what to do =做什么，做什么事情，强调做某某事情的内容 1.It's not your place to tell me how to do my job. 你没有义务教训我怎样干。 2. He helped me enormously with advice on how to do ideological work. 他告诉我怎样做思想工作，对我有很大帮助。 3. Please explain where to begin and how to do it. 请说明从什么地方开始，以及如何做。 4. If you don't know how to do it, don't fool with it. 你要是不会干就别胡来。 5. Let's put our heads together and see how to do it. 大家来想办法。 6. No matter how hard it is, I'll learn how to do it. 什么难学不难学，我保证学会。 7. Give us some pointers on how to do the job. 这工作怎么搞法，你给我们出一些点子。 8. If you watch carefully you will see how to do it. 如果你仔细观察，你就会看出如何做此事了。 9. Please explain to me where to begin and how to do it. 请向我说明从哪里开始以及怎样做。 10. I should like to know how to do it well. 我很想知道怎样才能做好这件事。 答题不易，如果非常满意，请立即采纳，谢谢！