装有速度传感器，用于采煤机的（）和（）保护，使采煤机安全可靠地工作。
参考答案：超速；差速
翻译以下句子。
1. The boy delivers newspapers every morning.
_____________________________________________
2. Comrade Yang delivered the opening speech.
3. She went to a neighboring village to deliver a baby.
根据翻译,用deliver 完成句子。
4. Some new books _____ to the school.
某些新书已经被送到学校.
5. The actor _____ his speech in a soft voice yesterday.
昨天一位演员用他那柔和的声音做了演说.
