13．Helen was very rude to me. I refuse to speak to her again __________ she says sorry.
A．until B．if C．because D．since
【答案】A
【解析】
句意：海伦对我粗鲁，我拒绝跟她再次说话，直到她向我道歉为止。
考查连词辨析。until 直到……才；if 如果；because 因为；since 自从，既然。结合句意可知，此句是until引导的时间状语从句，故答案选A。
14．I learnt to swim when I was six. I ___________ by my mother.
A．am taught B．was taught C．will be taught D．have taught
【答案】B
【解析】
句意：我六岁时学习游泳，是我妈妈教我的。
考查动词时态及语态。A. am taught 一般现在时的被动语态；B. was taught 一般过去时的被动语态；C. will be taught 一般将来时的被动语态；D. have taught 现在完成时的主动语态。由“when I was six”可知要用过去时态，主语为I，是teach动作的接受者，因此谓语应用过去式的被动语态。故答案选B。
15．Every time Tom is late, he'll ___________ an excuse. So I wonder what his excuse is this time.
A．set up B．put up C．take up D．make up
【答案】D
【解析】句意：每当汤姆迟到，他总要编造一个理由。所以我想知道他这次的理由是什么。考查动词短语辨析。set up 建立；put up 张贴，举起，建造；take up 开始从事，占领；make up 编造。宾语为an excuse，借口需要编造。故选D。