A:先天性行为
B:学习行为
C:本能
D:捕食行为
①人生自古谁无死,留取丹心照汗青 ②少小离家老大回,乡音无改鬓毛衰
③少壮不努力,老大徒伤悲 ④盛年不重来,一日难再晨
-- Attention, please! I have good news for you about your flight.
-- ?
当如图所示的手摇发电机大轮缓慢转动时,演示电流表的指针将( )