妈妈带着小丽去公园。早晨离家时是整时，时针和分针恰好成180度的角；下午回家也是整时，时针和分针恰好成90度角。小丽从离家到回家经过了（ ）小时。
9
缺铁性贫血时细胞形态学分类属于
A．小细胞正色素性贫血B．小细胞低色素性贫血C．正细胞正色素性贫血D．大细胞低色素性贫血E．大细胞性贫血
TCP (Transmission Control Protocol) was specifically designed to provide a reliable end-to-end byte stream over a(n) （）.
A.IP address
B.reliable network
C.socket
D.unreliable internetwork
