A项更符合主题句的特点。主题句的特点是：（1）It names the topic in the paragraph, telling the reader what the paragraph is about.（2）It contains a controlling idea that commits the paragraph to a specific aspect of the topic. A controlling idea is a key word or phrase that expresses the basic point of a paragraph. （3）It tells the reader what to expect in the paragraph. （4）It usually is the most general and most important statement in the paragraph.其中B选项不符合第二项特点，因为much about 很宽泛，没有一个具体的点，而且句中有don't seem to不太适合作为结论来使用；C选项只是客观陈述了一个现象，不是一个观点，所以不符合主题句的特点。D选项有些细节化，构不成一个观点性的句子。