1 D they would like to see是定语从句,修饰plan,所以整句话缺少谓语动词,排除B C,且根据At the Nuclear Security Summit,为过去时间,所以用一般过去时.
2 B pay attention to 中to是介词,后面跟动名词.prevent sb or sth from doing sth,在考虑被动态选B
3 B B选项中省略that,实际上是dream后面跟了一个that引导的宾语从句.dream的用法,dream of/about doing sth ,若选C,则少了个of或about
4D be allowed to do sth