I went there in 1984 and that was the merely occasion when I the journey in exactly two

问题补充：

I went there in 1984, and that was the merely occasion when I the journey in exactly two days.

A. must take

B. must have made

C. was able to make

D. could take

答案：

A. must take

B. must have made

(答案→)C. was able to make

D. could take

解析：考查情态动词：句意：我在1984年到了那里，这是我唯一的机会可以有两天的旅行。这里表示过去能够做而且成功了。be able to 与can用法与区别， be able to 强调努力而的能力，而can则强调自身已的能力。选C。