could have done "本来可以……"(表示过去没有实现的可能)。 might have done "本来可能……;本来应该或可以做某事"(实际没有发生;含有轻微的责备语气。 should/ought to have done "本来该做某事"(而实际未做) should not/ought not to have done "本来不该做"(实际...
23. They have been doing some excellent work on the prototype. 他们为原型的研发做出了杰出贡献。 24. We recently did a survey and the results were astonishing. 最近我们做了...
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