王太觉得这句话有问题呀.
我们可以说He is unhappy because he has to go to Suzhou on a business trip.这里的时态has to指目前的情况.
或：He is unhappy because he will have to go to Suzhou on a business trip.指即将发生的情况
he's had to=he has had to 完成时,没人这么用.has to 没有被动语态.