$\text{Đáp án+Giải thích các bước giải:}$

$4.$ $Both$ $the$ $teacher$ $and$ $the$ $students$ $are$ $looking$ $forward$ $to$ $the$ $field$ $trip$ $to$ $the$ $museum$ $next$ $week.$

$5.$ $Lan$ $asked$ $me$ $if$ $I$ $had$ $ever$ $taken$ $part$ $in$ $any$ $environmental$ $protection$ $volunteer$ $activities$ $before.$

$6.$ $Not$ $until$ $I$ $arrived$ $at$ $the$ $cinema$ $did$ $I$ $realize$ $that$ $I$ $had$ $left$ $my$ $ticket$ $at$ $home.$

$7.$ $At$ $this$ $time$ $next$ $week,$ $we$ $will$ $be$ $enjoying$ $our$ $summer$ $holiday$ $in$ $a$ $peaceful$ $mountain$ $village.$

$8.$ $If$ $I$ $were$ $you,$ $I$ $would$ $reduce$ $the$ $amount$ $of$ $plastic$ $waste$ $to$ $help$ $the$ $city$ $become$ $cleaner$ $and$ $more$ $beautiful.$

$9.$ $The$ $excessive$ $use$ $of$ $modern$ $electronic$ $devices$ $is$ $believed$ $to$ $cause$ $health$ $problems$ $for$ $teenagers.$

$10.$ $Three-quarters$ $of$ $the$ $water$ $on$ $the$ $Earth's$ $surface$ $is$ $polluted$ $by$ $industrial$ $waste.$

$11.$ $The$ $director$ $wanted$ $to$ $know$ $who$ $was$ $responsible$ $for$ $the$ $delay$ $of$ $this$ $nature$ $conservation$ $project.$

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