Ex 1.
1,B-taching
2,A-exciting
3,B-how
4,C-most
5,B-for
Ex2
1, ... in listening to music.
2, ...that i is very challanging to climb the mountain alone
3,... ever watched 'Iron man" before.
4,...that bird watching is not as interesting as arranging flower.
5,... been collected old coins for 5 years.
6,... to play the guitar 3 years ago.
7,... are not usually as expensive as mangoes.
8,... to smoke 3 years ago.
9,... he was ill,.....
10,....the facts that he was hungry,he didn' eat much.