染色质与（）是细胞中同一物质在不同时期呈现的两种不同形态。
参考答案：染色体
Two thirds of the subway construction________so far and people will enjoy a fast and convenient trip
under the city early next year. [ ]
A. have been completed
B. is being completed
C. has been completed
D. will be completed
配送中心的主要工作有（）、（）、（）、（）。
