Charlie is so young that he can't take the underground alone．（改为简单句）
Charlie is to take the underground alone．
You have done so excellent work． （ 改为感叹句）
excellent you have done!
Li Hua's mother took part in Hubei medical aids in February． （对划线部分提问）
took part in Hubei medical aids in February？
You'd better tell us about today's discussion． （改为否定句）
You'd better us about today's discussion．
The teachers are still taking about where they will hold the concert． （改为简单句）
The teachers are still talking about hold the concert．
It is fine weather to row a boat on the lake． （改为感叹句）
weather it is to row a boat on the lake!