重点讲解:
1. switch on 打开,开启(电灯等);
He didn't bother to switch on the light.
他懒得去开灯 。
2. be exposed to 使暴露于;
They were exposed to radioactive fallout during nuclear weapons tests.
在核武器试验中他们暴露在放射性尘埃之下 。
3. send out 发出(信号、声音、光、热等);
Like bats, they send out sound waves and make sense of their environment from the echoes they receive back.
像蝙蝠一样,它们发出声波,然后根据收到的回音来了解周围的环境 。
4. convert into (使)改变;更改;(使)转变;
The signal will be converted into digital code.
信号会被转变为数字代码 。
n. 分数,小部分,破片