问几道高中非谓语动词的英语题 希望附有讲解

1.______ in the mountains for a week, the two students were finally saved by the local police.
A. having lost (= the the two students had lost)
不可选。 表示早于被警察救出，但是 lose 是及物动词，后面有 themselves 才可以成立。
B. lost(= the the two students were lost )
可选。be lost 表示迷路。
C. being lost (= the the two students were losing )
不可选。既表示被警察救出同时发生，有没有宾语 themselves。
D. losing (= the the two students lost )
不可选。表示曾经丢失过某种东西（但没有宾语），与警察救援没有关系。

2. It is worth condering what makes "convenience " foods so popular, and ______ better ones of your own.
答案： C. introducing
it is worth 后带有两个并列的动名词，其他形式不符合结构要求。
即： It is worth condering ... and introducing ...值得考虑...并采用....

这句话还请翻译一下

3.---Can those ______ at the back of the classroom bear me?
---No problem.
答案：C. seated
1）seated at the back of the classroom 是过去分词短语用作后置定语，等于定语从句 who are seated at the back of the classroom ，