A: where was it that
B:that was it where
C:where it was that
D:that was it where
如图,在△A1B1C1中,已知A1B1=7,B1C1=4,A1C1=5,依次连接△A1B1C1三边中点,得△A2B2C2,再依次连接△A2B2C2的三边中点得△A3B3C3,…,则△A5B5C5的周长为____ .
与120°E经线构成经线圈的经线是( )
日——____
辶——____
口——____
足——____