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)
不可選.表示早于被警察救出,但是 lose 是及物動詞,后面有 themselves 才可以成立.
B.lost(= the the two students were lost )
可選.be lost 表示迷路.
C.being lost (= the the two students were losing )
不可選.既表示被警察救出同時發(fā)生,有沒有賓語 themselves.
D.losing (= the the two students lost )
不可選.表示曾經(jīng)丟失過某種東西（但沒有賓語）,與警察救援沒有關(guān)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 后帶有兩個并列的動名詞,其他形式不符合結(jié)構(gòu)要求.
即：It is worth condering ...and introducing ...值得考慮...并采用.
這句話還請翻譯一下
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 是過去分詞短語用作后置定語,等于定語從句 who are seated at the back of the classroom ,注意 seat是及物動詞,意思是“使...就座、被安排就座”,所以定語的意思是“使他們就座于教室后面的（那些人）”
2）句子主體是：Can those hear me?那些人聽得到我（講課嗎?）
3）sit/sat 是不及物動詞,指的是行為者的具體動作,用在此處不對.
翻譯：坐在教室后面的那些人聽得到我嗎?