内容介绍：单项选择题W W W. TD XL. CN课后练习四参考答案及解析（本练习匹配英语基础四课程，建议 30 分钟内完成)1. “Have you seenpen? I left it here this morning.” “Is itfound it in the corner.”A. a; theB. the; theC. a; aD. the; asblack one? I2. A libra