My calculations were based on the ______ that house prices would remain steady.

We have moved into a four-room flat so far. Our room is between _____.

He made a _____ of five thousand dollars on the deal.

This law which has just been passed is a that the government will pay more attention to protecting wildlife．

  In this experiment, the famous professor showed three different ________ to the study of physics.(2012·河北保定中学月考)