A：室温约48℃
B：一张理综答题卡的质量约500g
C：门的高度约为4m
D：一盏日光灯的额定功率约40W
下列命题中，真命题是（ ）.
方程2x2=4x的根为（ ）
选词填空。
A. This is Mary. She's nine. She's tall. She's thin.
B. This is Danny. He's six. He's short. He's fat.
C. This is Eddie. He's nine. He's short. He's thin.
