Other confusing measure words: *层 céng and 栋 dòng both are used for buildings. Are they interchangeable? How to know which to use? ------ No. 层 céng means the numbers of floor for one building, and 栋 dòng means the numbers of buildings * 颗 kē and 粒 li refer to small objects.How to distinguish between them? ------ Sometimes they are same. To distinguish them, just using them more and remember them.