成人心肺复苏时胸外按压的深度为（）
A.胸廓前、后径的一半
B.1～2cm
C.2～3cm
D.3～4cm
E.4～5cm
参考答案：E
— What's he wearing?
— ___________________[ ]
A. He's wearing a green shirt.
B. I am wearing a green shirt.
C. She's wearing a green blouse.
把下面各数改写成“万”或“亿”作单位的数，再保留一位小数．
605470=______万≈______万
459600000=______亿≈______亿．
