wh-question word 一問....

' What to do' is just a pronoun used to substitude the words that you wiil mention, often appear with a subject

E.g: From now on, < > is to reduce the emmision of greenhouse gas.

Furthermore, ' How to do it' is imformal as ' How do we do it' is a written phrase

2007-01-30 17:29:55 補充：
E.g: From now on, ' WHAT WE HAVE TO DO' is to reduce the emmision of greenhouse gas.

how to do something , what to do 等 ,
不能作為疑問句用 ,
是名詞片語的一種 ,

通常的型式是 :
主語 + 動詞 + ( how / what / when / where / which / why + 不定式 ) ,
作賓語用 ,

例如 :

He discovered ( how to open the safe ) ,
他發現了 ( 如何打開保險箱 ) ,

I found out ( where to buy fruit cheaply ) ,
我找到了 ( 那個地方買廉價水果 ) ,

I did not know ( when to switch the machine off ) ,
我不知道 ( 甚麽時候關機器 ) ,

She could not think ( what to say ) ,
她想不出 ( 說甚麽 ) ,