我发到这样一个case, 一点头绪都没有，查了fasb no.13, 还是不知道该怎么回答， 姐妹们帮帮忙啊。

Maples and Trumpet

Maples Model Development Company (“MM”) entered into a 99-year ground lease with Don “the Duck” Trumpet as lessor. MM intends to construct a building and make other significant leasehold improvements. Being an astute real estate tycoon, the Duck insisted that the terms of the lease include provisions for increases in the base rent every 10 years for the duration of the lease. The base rent increases will be based on the Consumer Price Index (“CPI”), but shall not be less than 20 percent nor greater than 60 percent for a 10-year period.

In the recent past, the Duck entered into a similar long duration arrangement and had a less than favorable experience when the agreement was terminated because of a dispute between the Duck and the lessee. Accordingly, the Duck was unwilling to enter into any long-term commitment with MM without imposing some economic penalty on MM should MM decide to terminate the arrangement. As a result, the lease was structured to provide MM the right to terminate the agreement at any time. However, in the event that MM elects to exercise the right to terminate the lease, MM would be required to transfer title to the building and related leasehold improvements to the Duck.

Subsequent to entering into the lease, MM constructed a seven-story office building on the land subject to the terms of the ground lease. For book purposes, the building and related leasehold improvements were assigned a 40-year depreciable life.

Due to the cancellation provisions of the ground lease agreement, MM is having difficulty in determining the lease term for accounting proposes. Additionally, due to the scheduled rent increase, MM is unsure of how rent expense should be recognized over the lease term.

Required:
• What is the lease term of the ground lease?
• How should MM recognize rent expense over the lease term?