如果雷达的脉冲宽度为lμs时，不考虑光点尺寸，相应的距离分辨力为（）
A.37.5米
B.75米
C.15O米
D.300米
参考答案：C
Julie was good at German，French and Russian，all of ______ she spoke fluently.
A．who
B．whom
C．which
D．that
立式除油罐中污水停留时间要在（）之间。
A.2～5h
B.3～4h
C.1～3h
D.12～10h
