It will_____us_____in so many respects that I'm not sure how long it will take for us to catch up.
【正确答案】 B
【答案解析】解析:考查动词短语。set sb.back意为“阻碍……的进展;使受挫;延缓”,放到句中正合适。bring sb.back意为“把……送回”;turn sb.down意为“拒绝(提出建议、要求的人)”;bring sb.down意为“使落下;降低”。