The test was very difficult,but I ...pass it.a) was able to b) can c) could
The test was very difficult,but I ...pass it.a) was able to b) can c) could
was able to 强调有能力通过，而且通过了。
b
a
1. can只有两种时态, 即can 和could, 而be able to 有多种时态, 如was/were able to, will/shall be able to, have/has been able to等: I’ll be able to drive the car in a week. Through his diligent work, the deaf-mute has been able to read and write in a sign language. 2．表示过去通过努力终于做成了某事要用be able to，而不能用can。如： I was able to swim to the bank after the boat turned over. can 和be able to 都可以表示能力.can泛指一般的能力,而且只有两种形式,即:can, could．be able to 则主要指具体做到了某件事的能力，其形式主要是靠be 发生变化，所以形式比can 多．可以说：I can swim. I am able to swim. 但是不能说：All the people could escape from the big fire in time. 只能说：All the people were able to escape from the fire in time.
A
was able to 通过努力
a) was able to
理由：如果用can 或 could 是说有信心通过考试,是还没有考试过的状态.而 be able to 则可以是已经过去的状态.