Choose the best topic sentence from the four options below. Writ

Choose the best topic sentence from the four options below. Write the corresponding letter of your choice on the answer sheet.
A、With the 30% rule, you can keep a conversation flowing in a more natural way.
B、The conversation with no new information becomes like an upside-down pyramid.
C、When you don^ add new information, the conversation becomes extremely boring.
D、In some casual conversations, the same information is being repeated over and over.
【正确答案】：A
【题目解析】：主题句要符合以下四点：(1)完整性。用完整的句子表达一个完整的思想，这是对主题句起码的要求。(2)一定的具体性和概括性。主题句要明确、具体、内涵集中，所指单一，不要太笼统，也不要太具体。(3)清晰性。主题句要清晰明了，用词一定要恰当、贴切，不能含糊辞。(4)要有关键词。它不仅制约段落的写作方面和范围，而且是写作的导火线、突破口。关键词可以是一个词、一个词组或一个从句。所以A. With the 30% rule, you can keep a conversation flowing in a more natural way.最适合当主题句，意思是遵循30%原则，我们可以更自然地进行交谈。