目前国内常采用避孕效果较好的宫内节育器为
A．含抗菌防腐剂宫内节育器B．带孕酮宫内节育器C．不锈钢圆环D．含铜的宫内节育器E．麻花环
参考答案：D
That's the best way to ________ into the dangerous area.
A．get people get
B．stop people to get
C．keep people getting
D．prevent people getting
出现大便潜血试验阳性，其上消化道出血至少达到的数量是
A．5ml
B．10ml
C．20ml
D．50ml
E．60ml
