M型超声的二尖瓣水平波群不能构成哪项M型曲线
A．室间隔
B．左室后壁
C．主动脉瓣
D．右室前壁
E．二尖瓣前瓣
参考答案：C
句型转换。
1. My father played cards yesterday. (变为一般疑问句)
______________________________________________________________
2. Danny can fly a kite. (变为否定句)
3. The girl is singing a song. (对画线部分提问)
4. The stamp is ten yuan. (对画线部分提问)
2008+2007-2006-2005+2004+2003-2002-2001+……+4+3-2-1=( )
A．0
B．1
C．2007
D．2008
