1.sheaf
There is a sheaf of letter in his father's drawer.
2.incantation
I need an incantation to let me disappear as soon as possible.
3.yak
The yak is a good friend of people living in Tibet.
4.thumb through
He thumbed through the book to get the answer.
5.pasty
His friend's pasty face made me feel bad.
6.sputter
The flame sputtered out.
7.tic
The increasing people got a sick of face tic.
summary:
Harry read a letter which is about a magic course on Filch's desk secretly. He was fortunately not punished by Filch and found that it was Nick who had helped him.