胰体癌临床主要特点是
A.进行性无痛性黄疸
B.左上腹痛,反射到腰背夜间重
C.乏力、消瘦、贫血
D.肝和胆囊肿大
E.饱胀不适感
参考答案:B
There is strong evidence that the of a father increases the probability that a youngster will use drugs and engage in criminal activity.
A.absence
B.disappearance
C.attention
D.concern
一般导轨除保证本身精度外,还要保证与()及有关导轨的()精度。