解:原式=﹣1+4﹣3+3﹣2=﹣6+7=1.
根据理解,选择正确答案。
Found
Is this your book?
Please call Jim at 4953456
Is this your black bag?
Please call Susan.
Phone number:4765939.
Lost
My pencil case: blue and white
Call Tom at 4567800
A white watch.
Call Lisa at 4129856
小黄从赤道上的某点出发,先向正北方向走50千米,再向正西方向走50千米,接着向正南方向走50千米,最后向正东方向走50千米,此时小黄位于出发点的什么位置( )