heighten
verb [ I or T ] uk/ˈhaɪ.tən/ us/ˈhaɪ.t̬ən/
（使）（尤指某种情绪或效果）增强，加强
to increase or make something increase, especially an emotion or effect
The strong police presence only heightened the tension among the crowd. 大批警察的出现只能使人群更加紧张。