US GAAP and IFRS Differences

Got a question on the Volume 2 Schweser Exam book, question 30 to be specific. 1. Is expensing interest of self-constructed assets under US GAAP not allowed? 2. Why should there be no adjustment (as can be seen in the answers on page 63) to go from FIFO to LIFO? 3. Is FIFO accounting allowed under US GAAP? I thought I read everything in the Schweser/CFA books but where can I find whether changes have to be made if converting from IFRS to US GAAP? Thanks