单选题 His book was marred by the many remarks, which made us forget his main theme.
【正确答案】 C
【答案解析】(digressive离题的,枝节的)。句意为:许多离题的话使他的书大为减色,那些话使我们忘记了他的主题。A.inappropriate不适当的;B.humorous幽默的;D.opinionated固执己见的。