上、下消化道造影
参考答案：消化道造影所用造影剂是硫酸钡。消化道穿孔时禁用。观察胃、十二指肠用上消化道造影，观察大肠用钡剂灌肠检查。
补全对话。
Clark: What events do you ____1____ at your school?
David: We have an English Speech Contest each year.
Clark: ____2____ is it?
David: It's March 5th.
Clark: Do you have ___3_____ Art Festival?
David: Yes. It's March 17th. ___4___ we have a basketball game on March 10th.
Clark: When is your School Trip?
David: It's April 6th.
Clark: Is Linda's birthday ___5___in April?
David: Yes. It's April 18th.
世界贸易组织的前身是( )。
A．联合国经社理事会
B．海关合作理事会
C．关贸总协定
D．国际商会
