for A, which 指代exhibit, 而exhibit自己是不能activate 的。A out for B, awkward. 至于你说的同位语,那就更不可能。因为activation做同位语,那exhibit就是activation了,更说不过去。youknow,同位语是具有解释性的,他的antecedent必须和它相对应。 for C ,it 在语法上指代 Virtual Leonardo Project, (it 是完全指代)但你想,你都问了可以指代“exhibit吗?那就说明这个”it"有指代不清之嫌。out for D, i think this is a CORRECT answer, since the subject of "activate" should be "visitors ",therefor we use plural verb form "activate",if you used "activates" ,the subject would be "project "rather tan "vistor", and" to touch" is parallel with " (to) activate" E吧,它和A本质上是犯了一样的错误。