单选题
Looking ahead, the computer industry sees pure gold. Estimates for the number of personal computers in use by the end of the century run as high as 80 million. Then there are all the ______ industries: desks to hold computers, luggage to carry them, cleansers to polish them.
【正确答案】
D
【答案解析】[解析] D选项：auxiliary意为“辅助的，补充的，备用的”，如：She is an auxiliary nurse．(她是一名助理护士。)句意：此外还有各种辅助行业：安放电脑的书桌、携带电脑的行李和清洁电脑的清洁剂。故选D。
A选项：concessionary减价的；B选项：feasible可行的；C选项：hypothetical假设的。