Gone are the old days of solutions just working for my clients.意思是：只为客户解决问题而工作的日子将一去不复返了.
sth be gone:...消失了.在这里是表语放在句首,所以主谓倒装,主语是：the old days ,谓语是：are gone,但是表语放在句首后,主语谓语就倒装了,连系动词放在主语前面,主语的定语 of solutions just working for my clients 放在主语 the old days 后面.