SEM

例句：

1. 1.Our website has been optimized for search engines to improve its visibility.
   我们的网站已被优化以供搜索引擎使用，以提高其可见性。
2. 2. The company's marketing strategy is heavily focused on search engine marketing.
   该公司的营销策略主要集中在搜索引擎营销上。
3. 3.SEO and SEM are two important strategies for increasing website traffic.
   SEO和SEM是两个重要的策略，用于增加网站流量。