下列哪项是放射免疫显像的禁忌证（）。
A.早期癌肿
B.血清人抗鼠抗体阳性
C.手术后复发
D.久病体弱
E.癌肿广泛转移
参考答案：B
制作水晶甲时取粉时，水晶粉应聚集在（）
A.笔腹
B.笔根
C.笔尖
We are writing to the manager ______ the repairs recently carried out at the above address.
A．with the exception of
B．with the purpose of
C．with reference to
D．with a view to
