It is suggested that a heat－resistant material here () instead.A、is usedB、be usedC、must be usedD、used

propose和suggest的意思都是“建议”。例少:She suggested that he should adapt himself to his new conditions.她建议他适应新的情况。state“陈述，宣布”，例如，You'll have to state what exactly these terms mean.你须说明这些术语的确切意思是什么。say“说”。 announce“宣布，发布”，例如：The news was announced by the BBC.英国广播公司发布了这条消息。

Dear students，
I am writing this email to recommend you one of famous attractions of this city.I have lived here since 1990 and have been familiar with every corner of our city.Considering that you are the fresh visitor to our city,so it is advisable for you to have a look upon the Forbidden City.Firstly,the visit is beneficial for quickly learning the comprehensive perspective,such as the development of this city and its specific culture.What’s more,the site is the symbol of our special and sophisticated buildings,since these buildings are telling Chines peoples’the gradual changing habits and lifestyles.Thirdly,you'd better take a good sleep before the visit since the cite is large and will take you time to enjoy a rewarding tour.Once again,welcome to China.I do hope that you would find the site worthy of your visit.（149 words）
Sincerely yours,
Li Ming

indicate此处意为“通过某种迹象预示、表明”；B.hint“暗示，提升”，指通过微妙、含蓄的方式进行的揭示；[C]suggest指没有直截了当说出、但含有某种意思的“暗示”，接近imply；D.mean“意思是……，意味着……”。

本题考查的是对动词的认知能力。本句意思：这位工程师推荐在这儿建一座新的加油站。recommend推荐，例如：Can you recommend a good hotel？你能推荐一家好的旅店吗？A.ordered命令；B.insisted坚持主张；C.demanded要求；D.suggested建议。例如：May I suggest a white wine with this dish , Sir？ 先生，我给您推荐一种白葡萄酒来配这道菜，好吗？recommend和suggest意思最接近，所以选D。