在烧焦的鱼、肉中含有致癌物质3, 4一苯并芘, 其结构简式如图所示, 它是一种稠环芳香烃, 其分子式是（ ）
| A．C20H12 | B．C20H14 | C．C19H12 | D．C22H20 |
相关试题
It is often ______ that human beings are naturally equipped to speak.
| A．said | B．to say | C．saying | D．being said |
I can’t leave. She told me that I ______ stay here until she comes back.
| A．can | B．must | C．will | D．may |
—— Do you mind my opening the window? It’s a bit hot in here.
—— ______ , as a matter of fact
| A．Go ahead | B．Yes, my pleasure |
C．Yes, I do | D．Come on |
It’s high time you had your hair cut ; it’s getting _______ . 
| A．too much long | B．much too long |
C．long too much | D．too long much |
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