设a∈R,则“a=1”是“直线l1:ax+2y=0与直线l2:x+(a+1)y+ 发布时间:2017-04-10 16:47 │ 来源:www.tikuol.com 题型:选择题 问题: 设a∈R,则“a=1”是“直线l1:ax+2y=0与直线l2:x+(a+1)y+4=0平行”的( )A.充分不必要条件B.必要不充分条件C.充分必要条件D.既不充分又不必要条件
题型:选择题 The nurse is providing breast cancer education at a community facility. The American Cancer Society recommends that women get mammograms ().A.yearly after age 40.B.after the birth of the first child and every 2 years thereafter.C.after the first menstrual period and annually thereafter.D.every 3 years between ages 20 and 40 and annually thereafter. 查看答案