11.  We all were busy doing the maths excises day and night.

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

13.  It caped the letter "I".

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

15.  The composition was about how to protect the environment and it must be completed before next Wednesday.

16.  But, besides his, I had to do the chemical exercises which had eleven pages, had to do the English exercises which has twelve pages, had to go over the English lessons, had to go over the political lessons for he coming examination on next Tuesday.

17.  Oh, the busy Sunday!

18.  I can't finish all the work.

19.  The New Basket-ball Court.

20.  Since this week, our new basket-ball courts had entered the last constructional stage.