多数十二指肠出血是（）
A.呕血，便血
B.呕吐大量鲜血
C.柏油样便
D.便血
E.腹穿不凝血
参考答案：C
It seems that living green is _______ easy and affordable. A small step makes a big difference.
A．exactly
B．fortunately
C．surprisingly
D．hardly
全国性抗日战争爆发的标志是( )。
A．九·一八事变B．一·二八事变C．七七事变D．武汉会战
