根据汉语意思完成英文句子。
1. 微波炉可以用来煮饭。
A microwave oven can _____ _____ _____ cooking.
2. 你必须亲自去签收，他们不能邮寄过来就算完事。
You have to go sign for it _____ _____, they can't just mail it.
3. 人类怎么会说这么多种语言，这种情况是如何产生的呢？
How did it _____ _____ that humans speak so many different languages?
4. 老师告诉我们噪音对我们的耳朵伤害很大。
The teacher told us that noise _____ very _____ _____ our ears.
5. 在每一项发明被发明出来之前，爱迪生总要做大量的实验。
Before each invention was invented, Thomas Edison always did _____ _____ _____ _____.