题型:选择题 When a giraffe has _____ drink, it has to stand with its front legs wide apart in order to reach _____ water easily.A.不填;不填B.a; theC.the; 不填D.不填;the 查看答案
题型:选择题 如图所示,AB和CD是由同种材料制成的长度相同、横截面积不同的两段导体,比较这两段导体的电阻大小,有[ ]A.RAB>RCD B.RAB=RCD C.RAB<RCD D.无法判断 查看答案