工程采购项目履约担保采用履约担保形式的,其金额一般为合同金额的( )。
A.5%~25%
B.10%~30%
C.25%~45%
D.30%~50%
参考答案:D
肿瘤对放疗和化疗的敏感性取决于()。
A.瘤细胞总数中S/G期细胞的比例
B.肿瘤的来源
C.肿瘤实质与间质的比例
D.肿瘤的恶性程度
E.是否有坏死、钙化等继发改变
That day, we______ for the train station when Tom fell and hurt his legs badly.
A.have been leaving
B.were just about to leave
C.have left
D.are just going to leave