The baby was left in charge of my aunt.The baby was left in charge of my aunt.
Name the body parts: Look at the picture, and write the body part that is at each number. () 37. ____ 38. ____ 39. ____
能够将接收的光信号功率变换为电信号电流,实现光-电转换的光器件是
A negative charge ()moving, say, to the left is exactly equivalent to a positive charge moving to the right.