唐代长安城最宏伟富丽的建筑是[ ]
A．大雁塔
B．皇城
C．宫城
D．大明宫含元殿
答案：D
David likes country life and has decided to _____ farming.
A．go in for
B．go through
C．go on to
D．go with
什么叫无润滑压缩机，它适用于哪些场合，无润滑压缩机常用哪些自润滑材料？
