胰腺癌易发生早期转移的原因有()
A.胰腺周围脏器较多
B.胰腺血管、淋巴管丰富
C.胰腺腺泡无包膜
D.胰腺距离腹主动脉较近
E.胰腺癌发展较快
参考答案:B, C, E
Tomorrow is Tom's birthday. Have you got any idea _____ the party is to be held?[ ]
A. what
B. which
C. that
D. where
液压系统中的额定压力,可以划分为()等级别。
A.低压
B.中压
C.中高压
D.高压
E.超高压