错误地图:核心模式是“起点用 since,持续时长用 for”,并在从过去持续到现在时使用 have/has + 过去分词。4次独立记录中均出现,2次需提示,1次需两次重试;高优先。一次漏冠词未重复且不影响意思,本轮不练。优势:礼貌请求和时间词。
最小规则:since + 开始点(since Monday / since 10 p.m.);for + 一段时间(for two hours / for three days)。仍在继续时:I have waited for three days. 对比:I waited for three days 表示那段等待已结束或被当作过去事件。
练习题
- 选择:The printer has been offline ___ 9 a.m. A since B for
- 选择:We have waited ___ forty minutes. A since B for
- 填空:I ___ worked on the report ___ Tuesday.
- 填空:The room has been cold ___ two hours.
- 纠错:I have stayed here since three nights.
- 纠错:The lift is broken for Monday. 保留“从周一到现在”的原意。
- 完成一个真实但不敏感的句子:I have learned English ___ ___.
- 新情景:你在酒店前台说明热水从晚上8点起一直不可用。写一个完整英文句子。
提示阶梯:先问“开始点还是时长?”;再给 since/for;完整句仍错时给 Have/has + past participle + since/for 框架。每题先作答,再查看答案。错题须改正重说,并在两题后用新名词再练。
答案与理由:1 since,9 a.m.是起点;2 for,forty minutes是时长;3 have/since;4 for;5 for three nights;6 has been broken since Monday;7按真实内容核对起点或时长和现在完成时;8 The hot water has been unavailable since 8 p.m. “Unavailable”可替换为“not working”。掌握需连续4题无提示正确,覆盖since、for和完整现在完成时。第1、3、7天分别用交通、工作和酒店新情景各做4题;任何目标错则回到对比提示并重试。