A:元旦
B:“六•一”
C:“七•一”
D:国庆节
探讨反思:在我们的生活中还有哪些“一米线”现象?自己跨越过“一米线”吗?
看图片,选句子
A. Whose storybooks are these?
B. John is jumping.
C. Who is singing?
D. Look !Zoom is eating watermelon.
E. It is drinking water.
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命题“∀x∈R,x3-x2+1≤0”的否定是( )