During your lunchtime, which you usually spend at the university canteen in the presence of other students, one particular accounting student who was having difficulty with the textbook complained that he did not understand which costs were to be regarded as part of the acquisition cost of land, which costs were to be attributed to buildings under construction, and which were to be treated as an expense. Explain the basic principles to be followed. Are there any difficulties in applying these principles? Explain by providing examples.