1/You have taken part in this english-speaking club since last month -you began
2/My teacher hasn't talked to us since we left school
- My teacher last
3/The pikes have lived here since July 1st,1999
- The Pikes began
4/They haven't produce this kind of toy for a long time
-They stopped
5/It has not rained since this morning
-It stopped
6/The boys have played football since 2 o'clock
-The boys began

be more specific with your question.

innocence can be defined as the lack of sin, relating it with the lack of guilt, also it can be a synonime of naivety. most people agree that sins are made out of experiences, intentionally or not, as well as you stop being naive once certain things happen to you throughout your life. so, with this explained, the chosen answers are:

when the boy saw the effects of war, he no longer viewed life as innocent.

the loss of innocence is a result of gaining experience and making mistakes.

one way to define innocence is as a lack of worldly experience or sophistication.