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．

A．inspiration

B．compensation

C．occupation

D．regulation

自然循环蒸发器碱液的循环速度是依靠（）形成的。

A.压力差

B.重度差

C.循环差