转化炉烧嘴燃烧最好的火焰颜色是（）。
A．黄中带红点
B．蓝中带小红点
C．蓝白色
D．橙黄色
参考答案：C
Look, read and choose. (根据问题，看图选择答句)
1. What did you do last weekend?
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A. I visited my parents.
B. I visited my grandparents.
2. What did Wu Yifan do last weekend?
A. I did my homework.
B. He did his homework.
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