新疆出血热与汉坦病毒的相同点是
A．结构与培养特性
B．生物学特性
C．致病性
D．抗原性
E．传播媒介
参考答案：A
They have a beer together _____, talking about their separate life, but not often.[ ]
A. by and by
B. now and then
C. all the time
D. more or less
适用于管壁厚度为30mm的高压钢管焊接的坡口形式是（）。
A.只是V形
B.只是U形
C.只是I形
D.V形或U形
lking about their separate life, but not often.[ ]