辅修标记中（）为本次检修日期及检修单位简称。
A.左下格
B.左上格
C.右下格
D.右上格
参考答案：D
The barriers to trade may take any form including import duties，import licenses，export licenses，import quotas，tariffs，subsidies and( )to trade．
A．export system
B．international trade policy
C．import system
D．non-tariff barrier
何为真性菌尿？
