Condoms are an effective method of birth control if used with care.如果使用得当，避孕套是很有效的避孕手段。Although most condoms contain spermicide, there are some manufactured without.虽然多数避孕套含有杀精剂，但也有一些是不含的。Abstain from sex or use condoms....
A method of estimating Direction Arrival ( DOA ) based on Multistage Weiner Filtering ( MSWF ) is proposed.提出一种基于多级维纳滤波器 ( MSWF ) 的信号波达方向 ( DOA ) 估计算法....
In her dying days the old Queen unbent a little.在临死的那些日子里，年迈的女王态度稍缓和了一些。At the party even the professors unbent and told jokes.在晚会上,连教授们也变得轻松随和,讲些笑话.Trees with straight unbent trunks make the best lumber.树干笔直的树木是最好的木材材料....