农业银行债务融资工具准入类客户的外部评级须达到（）。
A.AA-
B.AA
C.AA+
D.AAA
参考答案：A
Why didn't you ask for help,____ trying to do it on your own? [ ]
A. rather than
B. other than
C. more than
D. less than
油罐液位（），易造成离心泵压力不足。
A.过高
B.过低
C.满罐
D.平稳
