现浇钢筋混凝土楼板主要可分为（）
A.板式楼板
B.梁板式楼板
C.井式楼板
D.保温楼板
E.无梁楼板
参考答案：A, B, C, E
信用等级为A级的用电客户，累计暂停时间从6个月可延长至（）个月。
A.7
B.8
C.9
D.10
—What do you think of genetically modified food (转基因食品)?
—We all think ______ is careless ______ some scientists to say it is safe before doing any experiment.
A．that, for
B．it, for
C．it, of
D．that, of
