1·It was a keen disappointment that I had to postpone the visit I pay to China in January.
我原打算在今年一月访问中国，后来我又不得不予以推迟，这使我深感失望。
2·It was a keen disappointment that I had to postpone the visit I had intended to pay to China in January.
我原打算在今年一月访问中国，后来我又不得不予以推迟，这使我深感失望。
3·It is a keen disappointment that I had to postpone the visit which I had intended to pay to China in January.
我原打算一月份访问中国，后来不得不推迟，这使我非常失望。
4·It was a keen disappointment when I had to postpone the visit which I had intended to pay to U. S. in February.
我原来计划今年二月访问美国，后来不得不推迟，这使我感到很扫兴。