A:
B:4
C:
D:5
图中甲是加入了抗凝剂的人体血液,乙是显微镜下观察到的血涂片,请据图回答:
朝鲜半岛的面积约为20万km2,地图上面积为20cm2,则该地图的比例尺为____。
如图,在平行四边形ABCD中,E为CD上一点,连接AE、BE、BD,且AE、BD交于点F,S△DEF:S△EBF:S△ABF=9:21:49,则DE:EC=( )
抄写下列句子。
①Time for music class.
②It's 8 o'clock .It's time for English class.
③Hurry up .It's time to go to school.
④It's 9:00 .It's time to go to bed.