1Suppose Professor Smith asked you to plan a debate on the theme of city traffic.
主干主语：（省略you）；谓语：suppose；宾语从句：Professor Smith asked you to plan a debate
结构祈使句省略主语you。suppose后接宾语从句（asked you to plan...），其中不定式to plan作asked的宾补；on the theme of city traffic为debate的后置定语，表主题限定。
译文假设史密斯教授让你策划一场以城市交通为主题的辩论。
考点suppose引导假设情景的宾语从句 · ask sb. to do不定式作宾补
2Write him an email to 1) suggest a specific topic with your reasons, and 2) tell him about your arrangements.
主干主语：（省略you）；谓语：write；间接宾语：him；直接宾语：an email
结构祈使句。to后接两个并列不定式作目的状语（suggest... and tell...），用1) 2) 分项列举；with your reasons修饰topic，表伴随内容。
译文给他写一封邮件，1）提出一个具体话题并说明理由，2）告知你的安排。
考点write sb. sth.双宾语结构 · 并列不定式作目的状语
3You should write about 100 words on the ANSWER SHEET.
主干主语：You；谓语：should write；宾语：about 100 words
结构情态动词should表建议。about 100 words作write的宾语；on the ANSWER SHEET为地点状语，限定书写位置。
译文你应在答题纸上写大约100词。
考点should表建议而非强制 · about表大约数量