哪个标记用于表示 HTML 文档的结束？( )
A:
B:
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D:
A:
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C:
D:
举一反三
- 下列化合物中哪个具有芳香性?( ) A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/f459ad245e0b421b8c408034349962e2.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/bbd772711b5845fa810365b224ba5b78.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/b9e471ec661a474697375481122a9ae9.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/9f0b52aec3cd4bc8b4d0da7317a27903.png" />
- 下列计算结果正确的是（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/46a91374ddb244fab2b2569e4e5c76da.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/13eeb2611b584e26b3cfda4c59f5e808.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/a2d3bc6d966b4e1aa1de82ec98f49aad.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/bf909bdba7004c3782fd3041cf6a8768.png" />
- 下列四种环烷烃的燃烧热,哪个最大?( ) A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/5be91d41d31b46d29452ee767404d3ee.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/2f2e0c6325944be08c159693eb20cb6a.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/0fe793ac8f0345ff832807bcc91a08b7.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/30e54f592a4d4081909d720eea5728c1.png" />
- 下列化合物中哪个烯醇式含量最高?( ) A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/b8c1f16c2fae420eba5626a1dd499b16.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/d5fe0bf9458a424eb10137d0d904c679.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/90c121bf3bb147e68c8a572383979ac1.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/9b3a09d479254944a84386bb59cfcfcc.png" />
- 丙烯与HBr加成,有过氧化物存在时,其主要产物是( )。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/0508a7ebaaa146a4bf377b608a89a47a.png" />,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/cb47e5a8d620401fbfe813768a96bc67.png" />各一半 B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/deb8c0a08872446f81a23feb1249b0f2.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/cb47e5a8d620401fbfe813768a96bc67.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202111/0508a7ebaaa146a4bf377b608a89a47a.png" />