Bacterial cells are small, one to two microns in diameter and this shows a picture of a common bacterium called E. Coli.

细菌细胞很小,直径只有一到两个微米,这张图片是一种常见细菌,大肠杆菌

耶鲁公开课 - 生物医学工程探索课程节选

Another situation is perhaps less positive, maybe more common.

另一种情况可能没这么正面了，但是更为常见。

I should have 课堂 - SpeakingMax英语口语达人

Valvular disease is not uncommon in the world; we'll talk about that a little bit.

心脏瓣膜疾病在世界上是一种常见的疾病,我们会讲到一些相关的内容

耶鲁公开课 - 生物医学工程探索课程节选

We might say, one set of approaches focus on ordinary, familiar, everyday facts about us.

我们可能会说,一种方法主要关注于我们自身普遍,常见的日常事实

耶鲁公开课 - 死亡课程节选

But what is a regime? Broadly speaking a regime indicates a form of government whether it is ruled by the one a few the many or as more common some mixture a combination of these three ruling powers.

但到底何谓政体？广义来说,政体象征着一种形式的政府,无论它独裁，寡头或多头掌政,或是更常见的混合体,综合上述三种统治权力。

耶鲁公开课 - 政治哲学导论课程节选

Malaria causes a million deaths per year, and schistosomiasis, which is a parasitic disease, is unfortunately a common cause of death in the world.

疟疾每年造成一百万死亡,而血吸虫病,这是一种寄生虫病,不幸的是,它是世界上很常见的死因

耶鲁公开课 - 生物医学工程探索课程节选