They were trying to remove harmful ______ from cigarettes.

American artist Jeremy Telford made a room with balloons． He got the____    from Bag End in Lord the Rings, which is a hole in the ground where a Hobbit（霍比特人）lives in the film．

Many people like white color as it is a ________ of purity.

— Mary told me she would meet me at yesterday’s  party. But she didn’t turn up. — It is a pity that she broke her ________ .

 --- I’ll buy you a ten-speed bicycle as a birthday present.  --- Is that a _________?  I wish you would not disappoint me.