11.  How I explained it yesterday?

12.  I thought it over.

13.  At last, I found the rror is in the printing.

14.  It caped the letter "I".

15.  When I told his this result, he opened his mouth, last fifteen seconds.

16.  Then, he said in a very dejected voice: "I have spent so much time on it.

17.  I had believes that it was a very hard question which few people could work out.

18.  " I thought I was lucky, because , when I work it yesterday .

19.  My eyes were so tired that I believed the question had the latter "I" by mistake.

20.  Otherwise, I would work it like Cuozongci.