下面关于女性站姿表达不正确的一项是（）
A.双手握于胸前
B.挺胸收腹
C.膝盖伸直
D.双脚靠拢或前后呈丁字步
参考答案：A
—What do you think of your trip to Hainan?
—Wonderful. We were all ________with the ________trip.
A．pleased; pleasant
B．pleasant; pleased
C．pleasing; pleased
D．pleasant; pleasing
输入输出接口PIO的输出驱动信号电压和极性为（）。
A.24V；“－”
B.24V；“+”
C.48V；“+”
D.48V；“－”
