下列有关动脉的特点的叙述,正确的是( ) A.管壁厚、弹性大、管内血流速度快 B 发布时间:2017-07-17 21:44 │ 来源:www.tikuol.com 题型:选择题 问题: 下列有关动脉的特点的叙述,正确的是( ) A.管壁厚、弹性大、管内血流速度快B.管壁厚、弹性小、管内血流速度快 C.管壁薄、弹性小,管内血流速度慢D.管壁薄、弹性小,管内血流速度慢
题型:选择题 —Is the letter from your mother?—Yes. But she ________ the letter herself, because she doesn't even know one word.A.needn't have writtenB.can't have writtenC.might not have writtenD.should not have written 查看答案