A.
a change in the state of the flip-flop can occur only at a clock pulse . 触发器状态的改变仅在时钟脉冲处发生。
B.
The state that the flip-flop goes to depends on the D input . 触发器的状态如何转换由D输入端决定。
C.
The output follows the D input at each clock pulse . 每个时钟脉冲处,输出都跟随输入D变化。
D.
All of these answers . 所有答案都对。