便隐血试验持续阳性，常见于
A．胃溃疡
B．十二指肠溃疡
C．胃癌
D．胃炎
E．肠道下端炎症
参考答案：C
Ladies and gentlemen, please fasten your seat belt. The plane __________.
A．takes off
B．is taking off
C．has taken off
D．took off
承包商提出的工期索赔是否正确应予批准的工期索赔为多少天？
