twelve
o'clock
`` Well , I 'll watch half the night , if you watch the other , '' said Bob . `` That 's fair , is n't it ? '' `` Yes . '' `` Then I shall lie down now , and you can call me when it 's twelve o'clock . '' `` But I sha n't know when it is , '' protested Dexter . `` Well , I ai n't particular , '' said Bob , stretching himself beneath the tree . `` Guess what you think 's fair half , and I 'll get up then . ''