A．NatureB．Self-RelianceC．WaldenD．Moby DickThoreau's ___……

单项选择题The smallest linguistic unit that can be used independently is ______.

单项选择题______ takes London as the setting in most of his novels.

单项选择题______ is the key conception in Christianity in which the three aspects of the same God are united as one.

单项选择题A traditional food enjoyed by Americans during Thanksgiving Day is ______.

单项选择题The first president in U. S. history who resigned because of a scandal is ______.