...whose intesert in mathematics does not reach beyond the conflict which arises when their favorite batsman tries to upset the law of gravity.
只有当他们喜欢的击球手试图推翻万有引力定律而受阻时，这些市民才会对数学感兴趣。
"只有当"是怎么翻译出来的，感觉少个unless什么的，求解答，谢谢。