7.【2019 •四川省自贡市】—Tom is always careless with his schoolwork．Could you help him？
   —No problem！I think he _______ to think twice before starting.
   A．should be told B．shouldn't be told C．should tell
【答案】
【解析】句意：——汤姆在功课上总是很粗心。你能够帮帮他吗？——没问题。我想应该告诉他在开始前要先三思。首先根据语境判断答语的意思是"没问题。我想应该告诉他在开始前要先三思。"主语 he是动作tell 的承受者，表示"被告知"，确定用被动语态，根据句意用情态动词should，含有情态动词的被动语态的构成是：主语+情态动词+be+动词的过去分词。故选：A。