逆变站接至不同远端交流站或逆变站的交流出线多于（）回时，不设置最后断路器保护。
A.1
B.2
C.3
D.4
参考答案：B
The parties to government procurement refer to the principal entities of allkinds that enjoy rights and undertake obligations in government procurement,including the procuring entities,the（）and the procuring agencies.
A.users
B.servers
C.producers
D.suppliers
简述建立采穗圃的方法。
