11.【答案】However hard some people in the audience tried to upset him

　　表示為難，此處用upset，當然我們也可以用made sb.in a difficult position，或embarrass sb.。

　　12.【答案】whether/if robots will one day have vision as good as human vision

　　whether/if引導后置的主語從句

　　13.【答案】wondering about his real purpose

　　leave sb.doing 讓繼續處于某種狀態;leave sb.to do sth.讓某人干某事

　　14.【答案】followed my advice, you would not be in trouble now.

　　虛擬語氣在if 引導的條件句中的用法。從句：if + 主語+ 動詞的過去式(be 用were)+ …… 主句：主語+ would(should, could, might)+ 動詞原形+ ……

　　15.【答案】of failure to fulfill its promise to improve urban traffic conditions/of failing to fulfill its promise to improve urban traffic conditions

　　本題考查對accuse的用法及短語fulfill one’s promise to…的掌握。Accuse“指責、控告”常用于accuse sb.of sth./doing sth.的結構，所以was accused of之后用failure和failing都可以。“實現……的承諾”用fulfill one’s promise to表示，to后接動詞原形。