蒸汽经过汽轮机喷嘴后，其压力、温度和焓（），速度和比体积增大，将蒸汽热能转换为动能。
A.升高
B.降低
C.不变
D.为零
参考答案：B
The young girl sitting next to me on the plane was very nervous.She ________before.[ ]
A. hasn't flown
B. didn't fly
C. hadn't flown
D. wasn't flying
停经2个月， * * 出血1周，子宫明显大于孕月，B超未见胎心搏动。应诊断为（）
A.早期妊娠
B.中期妊娠
C.晚期妊娠
D.异位妊娠
E.葡萄胎
