半双工
参考答案：
只用一根通信线，可以用于接收或发送，但不能同时在两个方向上传送的通信方式。
小红同学在做“测串联电路的电压”实验时，连接了如图所示的电路，接通开关后，发现L1亮度较大，L2亮度较小，对这一现象以下分析合理的是
A.灯泡L2发生了短路
B.灯泡L2发生了断路
C.灯泡L1两端的电压大于L2两端的电压
D.灯泡L2两端的电压大于L1两端的电压
按给出的要求变换下列句子，要求每空限填一词。
1. This is a watch. (变为复数形式)
__________ are some __________.
2. Can Cindy sing this song in Chinese?(作肯定回答)
__________, __________ can.
3. This sweater is $28. (对划线部分提问)
_________ __________ is this sweater?
4. He does his homework in the evening. (改为否定句)
He __________ __________ his homework in the evening.
5. Tile biology class isn't boring. (改为同一句)
The biology class __________ __________.
