Lydia, The following info is copied from another topic in BK, hope this gives you some ideas: 我今日收到個e-mail﹐係Johnsxn's既newsletter﹐話bb十五個月開始會轉訓一次晏覺.....
Naps
The need for sleeping during the day is slowly tapering off and your "two nap" child will slowly become a one-nap child, but there is no doubt he still needs a nap! There is nothing more trying than an over-tired child! Try to avoid late afternoon naps. His nap may last about 2 1/2 hours, but trying to restrict his nap may just result in a cranky over-tired child. It is important to have a special routine to prepare your child for his naptime as you should have for his nighttime bedtime as well.