1.retention n. 保持; 维持; 保留; (液体、热量等的)保持，阻滞; 记忆力; 记性;.
set the stage for 为……打好基础; 为…创造条件; 为…做好准备
Themes can help set the stage for visitor interaction and retention.
2.control over（为什么要用control over)
This plugin gives you control over the layout and capabilities of your posts and pages and is compatible with most of the themes available.
*control over someone or something
the power to direct or manage someone or something. (*Typically: get ~; have ~; give someone ~.) I have no control over Mary. I can't stop her from running away. Who gave you control over what goes on in this house?
3.factor in：将…计入; 将…考虑进
Another thing that you have to factor in is that you are increasing competition using the methods you develop too if you want to provide quality videos
4. marring v. 破坏; 毁坏; 损毁; 损害;
Because you’re using a child theme’s file to make changes to the site, you won’t have to worry about permanently marring the original.
5.riddled adj.布满(弹孔)的;遍布(枪眼)的; 充满了…的;满是…的;到处是…的
riddled with 饱受......的辛苦；充满
This means you won’t receive updates and you may use a theme riddled with exploits and security holes.
6.accentuate vt.着重; 强调; 使突出;
Explore the different plugins and themes that can accentuate your website.
China lent Russia $6bn (拢3.2bn) to help the Russian government renationalise the key Yuganskneftegas unit of oil group Yukos, it has been revealed.
8.shrink v. 收缩; 退缩; 畏缩; (使)缩水; 缩小; 皱缩; (使)减少
Germany's economy shrank 0.2% in the last three months of 2004, upsetting hopes of a sustained recovery.
德国经济在 2004 年最后三个月萎缩了 0.2%，打破了持续复苏的希望。