⑴ ____
⑵ ____
⑶ ____
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A. The boy can play ping-pong well.
B. The girl can draw a nice picture.
C. Mary can cook yummy food.
D. Bob can play basketball well.
E. That man can do some kung fu.
若一元二次方程x2+2x+a=0有实数根,则a的取值范围是( )
“中国不再隶属于任何‘天子’、或任何王朝,而归属于全体民众。”这描述了哪一历史事件的意义( )
⑴浓硫酸⑵浓盐酸⑶粗盐⑷生石灰⑸氢氢化钠⑹酒精