26（）

单项选择题Implied but not stated is that （）

A．laser-doppler radar is more accurate than microwave radar
B．microwave radar may not ensure absolute precision in measuring varying speeds
C．the light-beam radar can measure only slow speeds with accuracy
D．microwave radar operates at a higher frequency than laser-doppler radar

单项选择题25（）

A．a great deal of
B．a lot
C．a number of
D．a bit of