流线图上单汇辐合流场相当于（）。
A．低气压的流场
B．高气压的流场
C．低压槽的流场
D．高压脊的流场
参考答案：A
By the time Jack returned home from England, his son________from college.[ ]
A. graduated
B. has graduated
C. had been graduating
D. had graduated
主要由T-H蛋白构成的是（）
A.透明管型
B.细胞管型
C.肾衰管型
D.蜡样管型
E.结晶管型
