招标人采用邀请招标方式的,应当向( )个以上具备承担招标项目的能力、资信良好的特定法人或者其他组织发出投标邀请书。
A.2B.3C.4D.5
参考答案:B
句型转换。
1. Mr. Li began to teach English in this school in 1999. (同义句转换)
Mr. Li _______ ________ English in this school since 1999.
2. Our monitor has been a League member for two years. (同义句转换)
Our monitor ________ the League two years ago.
3. My grandpa had to collect water from the village well. (改为反意疑问句)
My grandpa had to collect water from the village well, _______ ________?
4. They can hardly believe it. (改为反意疑问句)
They can hardly believe it, _______ _______?
5. He spent hours cleaning out the refrigerator. (同义句转换)
He _______ hours _______ _______ out the refrigerator.
变压器的纵联差动保护应符合()要求:
A.应能躲过励磁涌流和外部短路产生的不平衡电流。
B.应能躲过变压器变二侧短路电流。
C.应具有电流回路断线和判别功能,并应能选择报警或允许差动保护动作跳闸。
D.差动保护的保护范围应包括变压器套管及其引出线,如不能包括引出线时,应采取快速切除故障的辅助措施。但在110kV电压等级的终端变电站和分支变电站,以及具有旁路母线的变电站在变压器退出工作由旁路断路器代替时,纵联差动保护可短时利用变压器套管电流互感器,此时套管和引线故障可由后备保护动作切除;如电网安全稳定运行有要求时,应将纵联差动保护切至旁路断路器的电流互感器。
E.应延时动作于断开变压器的各侧断路器。