“唯一能庆祝的就是Gerry要进监狱了”是对的
That said, the only celebrating Gerry(人名) is going to be able to do will be in prison.在celebrating后面省略了一个“that”,实际上这是一个省略了that的从句。celebrating在这里不是作动词用,而是+ing名词化了,实际应翻成“可庆祝的事”。
That said, the only celebrating that Gerry(人名) is going to be able to do will be in prison.这样看是不是清楚了?