1.Many students can't realize the importance of Englishuntil they _____school. 这道题为什么填leave而不是left? 2 .I met him on the street and I stopped ____him for some minutes.这道题为什么填to talk with而不是talking with? 3.I think thirty minutes _____enough for us. A are B were C would be Dwill be选哪个?求各位大神解答啊,明天考试啊啊啊啊啊啊啊啊啊啊啊急

1.Many students can't realize the importance of English
until they _____school. 这道题为什么填leave而不是left? 2 .I met him on the street and I stopped ____him for some minutes.这道题为什么填to talk with而不是talking with? 3.I think thirty minutes _____enough for us. A are B were C would be Dwill be选哪个?求各位大神解答啊,明天考试啊啊啊啊啊啊啊啊啊啊啊急