Choose tags by meaning, not looks: strong warns, em stresses, b and i just set apart.

Bold-looking text is not one idea. strong says this is important or urgent, em shifts the stress of a word in a sentence, b merely draws the eye without extra weight, and i marks an alternate voice such as a foreign term. Assistive tech may convey the first two, so use the one whose meaning you intend. Looks come from CSS.

Read it once, then a question tests whether the trick stuck.