消化管固有层中有腺体的器官，除外（）
A.食管
B.胃
C.空肠
D.结肠
E.直肠
参考答案：A
解析：食管腺与十二指肠腺均位于黏膜下层，不在固有层。
西餐酒具按质地可划分为（）等多种。
A.金银器酒杯
B.瓷酒杯
C.玻璃酒杯
D.锡器酒杯
An economist is developing a regression model of real GDP as a function of labor input. She needs to select a time series that represents the total amount of labor performed in a year. Which of the following is the most appropriate indicator of total labor performed that she can use for this model（）
A. Aggregate hours.
B. Average workweek.
C. Number of employed.
