A:合上开关K接通电路时,A2始终比A1亮
B:合上开关K接通电路时,A2先亮,A1后亮,最后一样亮
C:断开开关K切断电路时,A2先熄灭,A1过一会儿才熄灭
D:断开开关K切断电路时,A1和A2都要过一会儿才熄灭
There ______ a blue bag on a desk. ( )
自前证据显示,人类起源于( )