Ⅰ. 单项选择(共15分,每小题1分)
从下列各题所给的A、B、C、D四个选项中, 选出最佳选项。
(  )1. This pair of shoes _______ Li Lei’s. Your shoes ________ under the bed.
        A. is; are        B. are; are       C. is; is          D. are; is
(  )2. The man reached _______ a small village __________ a cold morning.
        A. in; on        B. /; in        C. at; in          D. /; on
(  )3. The scientists from ________ United States live on ________ eighth floor of the building. 
        A. the; an        B. an; the           C. the; the      D. an; an
(  )4. I found ______ not very difficult to solve the problem.
        A. that    B. it     C. myself      D. this
(  )5. —Is it your eraser, Simon? 
        —No. __________ is in my pencil case. It’s _________.
        A. My; Mary     B. Mine; Mary’s      C. My; Mary’s      D. Mine; Mary