物理上常通过声波的波形图来反映声波的特点.如图所示,根据甲、乙两个音叉振动时发出声音的波形图可以发现甲音叉比乙音叉发声的音调 ,乙音叉比甲音叉发声的响度 .
高;大
---- Occasions are rare _____ I can spend a day with my daughter.
---- You should spare some time to accompany her.
A.when
B.where
C.which
D.that
孟德尔用纯种黄圆豌豆和纯种绿皱豌豆做杂交实验,F2中出现的不同于亲本的类型是:()
A.黄绿、圆皱
B.黄圆、圆皱
C.黄绿、绿圆
D.黄皱、绿圆