APM30H热交换一次下电,6个20A的空开分别控制6路直流输出给()个RRU供电。
A.2
B.3
C.6
D.9
参考答案:C
Dogs are our good friends as they can keep ______ with us when we are lonely.
A.ambition
B.company
C.balance
D.distinction
预防支气管哮喘发作的首选药物是
A.肾上腺素
B.异丙肾上腺素
C.特布他林
D.氢化可的松
E.氨茶碱