单项选择题
（）20 targets can be tracked at one time．When maximum tracking capacity is reached，no further acquisitions are possible.
A.As many as B.So many as C.As much as D.As more as
单项选择题 What will NOT induce errors into a doppler sonar log?（）
单项选择题 The microsecond unit of time is used in radar applications. The microsecond represents which of the following?（）.
单项选择题 The minimum range at which a target can be detected is basically determined by which of the following?（）.
