----to wait for hours,she brought along a book to read.

这是一个以现在分词作状语的句子,Expecting to wait for hours,she brought along a book to read.相当于As she expected to wait for hours,she brought along a book to read.
B. To expect 是动词不定式,相当于in order to expect...而动词不定式位于句首是表目的的,此处不符合句意； C. Expects 是expect 的谓语形式,但此处无连词和主语,动词不能用谓语形式.
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