These tags have no visible presence (unless you add borders and such, as I have), but they act as a good marker for where content should go.

这些标记没有可见的表示形式(除非添加边框，像我这样做)，但它们很好地标记了内容的放置位置。

youdao

LDL cholesterol is not a good marker of cardiovascular risk in Type 1 diabetes.

LDL胆固醇不是1型糖尿病心血管风险的一个很好的标记。

youdao

Serum gastrin is a good marker to differentiate benign and malignant gastric diseases.

血清胃泌素是鉴别胃良恶性疾病的一个较好的标志物。

youdao

Sad to say, this is a pretty good marker of the current political mentality in much of America, no matter what the political orientation.

FORBES: Wikileaks' Friends Want to Borrow Your Money

The fact that this last feeling is so common in depression explains why being "stressed out" is such a good marker for major depression.

CNN: Stress has taken over: How can I turn my mind off?

"Alcohol was frequently positioned as a marker of the weekend, and a hangover as a marker of a good night out, " said lead researcher Professor Norma Daykin.

BBC: Drinker