对流场干扰最小的测流速仪器是哪种仪器?
A.毕托管
B.旋桨式流速仪
C.激光测速仪
D.浮标测速
参考答案：C
解析：参看测速仪器相关内容。
What do you imagine ____________？
A．did he say
B．him saying that
C．he said
D．will he say
