This S／C may be______three months before its expiry .

题库:外贸英语 类型:最佳选择题 时间:2019-11-16 15:47:07 免费下载:《模拟试题五》Word试卷

This S／C may be______three months before its expiry .
A.postponed
B.prolonged
C.expanded
D.renewed

本题关键词:TN-S-C系统,TN-C-S系统,TN-C-S三相供电,S草,荠s,S波,S-苷,荠s苗,S-O-R,S-苷键;