There _____ a pen and some books on the 发布时间:2017-06-23 10:25 │ 来源:www.tikuol.com 题型:选择题 问题: There _____ a pen and some books on the desk. [ ]A. have B. has C. is D. are
题型:选择题 图是血液循环和气体交换示意图,请据图回答:(1)图中5指的是______,内流______血图中7指的是______,内流______血(2)血液由2射出,流径5、6到了循环途经叫______;血液由4射出,流经7、8到1的途径叫______(3)由M到N处,血液成分发生了变化.血变成了______血.(4)在心脏四腔中壁最厚的是____________,内含______血. 查看答案