have a crush on的意思是指“愛上了……，對……有好感，喜歡上了……”

英文解釋：
to have a feeling of romantic love for someone, especially someone you do not know well.

When you have a crush on someone, you like that person. You usually feel uneasy and try to get attencion around that person. Sometimes, it's hard to stop thinking about them.

例句：
Do you still have a crush on Jessica?
你還喜歡著杰西卡嗎？

Sometimes the kids think they fall in love when they have a crush on someone else in the class, when they're eight or ten years old or something like that.
八歲或十歲左右的孩子有時會迷戀班上某個人，然后就以為自己戀愛了。

You friend Jack Turner seems to have a crush on Susan Tompkins.
你的朋友杰克·特納好像迷戀上了蘇珊·湯普金斯。