Building a house costs quite a lot of money. Suppose you plan to build a house. Your first step will be to find a right piece of land. Your choice will depend on many different things. You will probably try to find a sunny place, with pleasant surroundings near shops and bus stops, not too far from your friends and the place where you work. Next you will find a good builder, and together with the builder you will work out a plan. The builder will draw the plan. It will show the number of rooms, their position and size, and other parts, which must be noticed, such as windows, doors, and electric outlets. The builder will work out how much money is needed to build your house. He will work out the cost of the wood, bricks, the glass, and everything else that must be used in building the house. Later on, when he starts to build, this estimate must be corrected and revised. His estimate is based on existing prices, but prices of such things may change, and many other things may happen between the time when he makes the estimate and the time when he builds the house. When the builder gives his estimate, you may wish to change your plan. (You may also wish to change your builder, if his estimate is too high! ) You may find that the house you wanted at first costs too much, or that you can spend a little more and add something to your plan. The builder's estimate depends on the plan, but the final plan depends on the builder's estimate. When the builder starts to build a house, his estimate will have to be corrected and revised because _______.
A.it is wrongly worked out by a workman B.the future owner of the house thinks the estimate is so high that he cannot afford the building C.the prices of building materials and the expenses of labor may be different from the original prices and expenses D.estimates are usually mistaken in the beginning