蟹的卫星DNA为只有AT两个碱基的重复序列组成。 ( )
参考答案：对
Just as sound travels through the air in waves, electricity travels through the air in ______ radio waves.
A．what is called
B．which is called
C．what it is called
D．which it is called
在计划完成后进行的评价性控制是（ ）
A．前馈控制
B．现场控制
C．预防控制
D．反馈控制
