—More and more people come to visit Jingzhou Ancient City. —That's true. It has become the of Jingzhou.
A:effort
B:praise
C:courage
D:pride
如图,在 ▱ ABCD中,对角线AC、BD相交于点O,E为AB的中点,且OE=5,则BC的长为( ).
甲船从A港出发,每小时行18千米,5小时后,乙船出发9小时追上甲船,乙船的速度是____ .
超声波是人耳听不见的声音,但它有着广泛的应用,在下列设备中,利用超声波工作的是( )