In the fast-evolving tech sector, companies must have their finger on the pulse of new trends.

have 是动词，意思是"拥有、具备"。 their 是形容词性物主代词，意思是"他们的"。 finger 是名词，意思是"手指"。 on 是介词，意思是"在...上"。 the 是定冠词，表示特指。 pulse 是名词，意思是"脉搏"。 have one's finger on the pulse 是一个固定短语，字面意思是"手指放在脉搏上"，比喻"密切关注、及时掌握(某领域的最新动态)"。