根据提示，完成单词。

What's the ________(sth．which makes your voice much louder)made of?

根据提示，完成单词。

Do you know where the ________(the way out of a room or a building)is in this theatre?

根据提示，完成单词。

The ________(the people who come to watch a show)in the theatre were very excited when they saw their favourite singers．

根据提示，完成单词。

Do you know that ________(a person who performs in a show)in white?

根据提示，完成单词。

Jay Chou is dancing on the ________(an area where actors, dancers, singers, etc．perform)．

用适当的介词填空。

Rice must be harvested ________ the right time．

用适当的介词填空。

He was working ________ the Maths problem when the light went out．

用适当的介词填空。

He was to be a host ________ a charity show．

用适当的介词填空。

We had a lot of support ________ local business．

用适当的介词填空。

________ meals, you should wash your hands．