虱传回归热的病原体是() A.波斯包柔体 B.赫姆斯包柔体 C.杜通包柔体 D.回归 发布时间:2017-06-04 15:26 │ 来源:www.tikuol.com 题型:单项选择题 问题: 虱传回归热的病原体是()A.波斯包柔体B.赫姆斯包柔体C.杜通包柔体D.回归热包柔体E.拉迪什夫包柔体
题型:单项选择题 已知a、b、c是△ABC三边的长,则方程ax2+(b+c)x+a4=0的根的情况为( )A.没有实数根B.有两个相等的正实数根C.有两个不相等的负实数根D.有两个异号的实数根 查看答案
题型:单项选择题 Do you think the problem is ______? If you think hard, you'll find it ______ to work out. [ ]A. hard; easyB. easy; hard C. hardly; easily D. hard; easily 查看答案