从句意上理解是很正确的 activate the animated functions of the piece的意思是激活图片的动画效果 这个动作是可以由visitors完成的 所以证实了to touch 和to activate可以并列使用 省略第二个 to。而thereby又昭示了两个并列动作的先后因果关系~
我觉得winner2006的分析是有一定道理的,如果用thereby activate,那很有可能是将activate和touch并列了,作为encourage的宾语补足语,但是我觉得这里就有逻辑问题了,encourage visitors to touch没问题,但是encourage visitors to activate 就有问题了,activate不应该是visitors touch造成的必然结果吗?难道不是一touch就会activate的吗?所以我觉得应该是activates,其主语为整个一个句子:(encourage)visitors to touch the exhibit,因果前后关系应该在这二者之间才对。open to discussion
OG12选D,分析如下: The relative pronoun which requires an antecedent, and there is none provided in this sentence. It makes more sense to make the visitors the agents responsible for the action of both the verbs—touch and activate. Because to "touch''is an infinitive, the second verb form must be, as well, though the to may be implied. D Correct. The agent of the action is clearly indicated by the grammatical structure of the sentence; visitors are encouraged to "touch"... and thereby (to) activate.